JP7487828B2 - Electronic device, calculation support method and program - Google Patents

Description

The present invention relates to an electronic device, a calculation assistance method , and a program.

Some recent tax calculators (electronic calculators) are equipped with a function for calculating tax using a preset tax rate. For example, the calculator described in Patent Document 1 performs any four arithmetic operation, and while the numerical value (amount) to be multiplied is displayed, when the tax-inclusive key (confirmation key) is operated, the tax-inclusive amount based on the displayed numerical value and a first tax rate is calculated and displayed. Similarly, when the tax-inclusive key (confirmation key) is operated again, the tax-inclusive amount based on the displayed numerical value and a second tax rate is calculated and displayed.

The tax calculator described in the cited document 2 is provided with multiple tax calculation keys (tax-inclusive calculation key, tax-exclusive calculation key) corresponding to multiple tax rates, and a dedicated key for calculating the total amount including tax (tax calculation total key). The tax calculator calculates and displays the tax-inclusive amount for each tax rate based on the values input individually in response to the operation of each tax calculation key. Furthermore, the tax calculator calculates and displays the total tax-inclusive amount for each tax rate .

Japanese Patent Application Laid-Open No. 10-143472 JP 2017-174225 A

When calculating each tax-inclusive amount that is the basis for the total tax-inclusive amount for each tax rate, it may be necessary to perform an independent arithmetic operation.

The present invention has been made in consideration of the above-mentioned problems, and aims to provide an electronic device, a calculation support method, and a program that can prevent arithmetic operations from interfering with the derivation of the total, even if an arithmetic operation is performed independently of each tax-inclusive amount that is the basis for the total of the tax-inclusive amounts for each tax rate .

In order to solve the above problem, the electronic device of the present invention is an electronic device capable of performing a tax calculation to derive a tax-inclusive amount, a tax-exclusive amount or a tax amount as a calculation result, and is provided with: a storage control means for storing in a predetermined memory a first total value corresponding to the first tax rate and a second total value corresponding to the second tax rate by separating and adding up the calculation results when the instruction to execute the tax calculation is repeated between a case where a first operation key, to which a first tax rate is set as an instruction to execute the tax calculation, is operated following a numerical input as an instruction to execute the tax calculation, and a case where a second operation key, to which a second tax rate is set as an instruction to execute the tax calculation, is operated following a numerical input as an instruction to execute the tax calculation; and a display control means for displaying the calculation result of the tax calculation on a predetermined display unit each time the instruction to execute the tax calculation is repeated, and the storage control means stores in the predetermined memory the first total value corresponding to the first tax rate and the second total value corresponding to the second tax rate so that, when a predetermined arithmetic operation is performed during the repetition, the calculation result of the tax calculation performed after the arithmetic operation is summed with the calculation result of the tax calculation performed before the arithmetic operation.
In addition, the calculation support method of the present invention is a calculation support method executed by an electronic device capable of executing tax calculation to derive a tax-inclusive amount, tax-exclusive amount or tax amount as a calculation result, and includes a storage control process for storing a first total value corresponding to the first tax rate and a second total value corresponding to the second tax rate in a predetermined memory by separating and adding up the calculation results when the instruction to execute the tax calculation is repeated between a case where a first operation key, to which a first tax rate is set as an instruction to execute the tax calculation, is operated following a numerical input as an instruction to execute the tax calculation, and a case where a second operation key, to which a second tax rate is set as an instruction to execute the tax calculation, is operated following a numerical input as an instruction to execute the tax calculation, and the first total value corresponding to the first tax rate and the second total value corresponding to the second tax rate are stored in a predetermined memory, and a display control process for displaying the calculation result of the tax calculation on a predetermined display unit each time the instruction to execute the tax calculation is repeated, and the storage control process is characterized in that, when a predetermined arithmetic operation is performed during the repetition, the first total value corresponding to the first tax rate and the second total value corresponding to the second tax rate are stored in the predetermined memory so that the calculation result of the tax calculation performed after the arithmetic operation is summed with the calculation result of the tax calculation performed before the arithmetic operation.
In addition, the program according to the present invention causes a computer of an electronic device capable of performing tax calculation to derive a tax-inclusive amount, a tax-exclusive amount or a tax amount as a calculation result to function as a storage control means for storing in a predetermined memory a first total value corresponding to the first tax rate and a second total value corresponding to the second tax rate by separating and adding up the calculation results when the instruction to execute the tax calculation is repeated between a case where a first operation key, to which a first tax rate is set, is operated as an instruction to execute the tax calculation, followed by a numerical input, and a case where a second operation key, to which a second tax rate is set, is operated as an instruction to execute the tax calculation, followed by a numerical input, and the like, and a display control means for displaying the calculation result of the tax calculation on a predetermined display unit each time the instruction to execute the tax calculation is repeated, and the storage control means is characterized in that it causes in the predetermined memory to store the first total value corresponding to the first tax rate and the second total value corresponding to the second tax rate, so that when a predetermined arithmetic operation is performed during the repetition, the calculation result of the tax calculation performed after the arithmetic operation is summed with the calculation result of the tax calculation performed before the arithmetic operation.

According to the present invention, it is possible to provide an electronic device, a calculation assistance method, and a program that can prevent arithmetic operations from interfering with the derivation of the total, even if an arithmetic operation is performed independently of each tax-inclusive amount that is the basis for the total of the tax-inclusive amounts for each tax rate.

FIG. 1 is a front view showing the external configuration of a tax calculator according to an embodiment of the present invention. FIG. 2 is a block diagram showing the configuration of an electronic circuit of the calculator according to the embodiment. 5 is a flowchart for explaining the operation of a tax calculation function of the calculator according to the embodiment. 5 is a flowchart for explaining the operation of a tax calculation function of the calculator according to the embodiment. 5 is a flowchart for explaining the operation of a tax calculation function of the calculator according to the embodiment. 5 is a flowchart for explaining the operation of a tax calculation function of the calculator according to the embodiment. 5 is a flowchart for explaining the operation of a tax calculation function of the calculator according to the embodiment. 11A to 11C are diagrams showing specific examples of input operations and displays to explain the tax calculation function of the calculator according to the embodiment. 11A to 11C are diagrams showing specific examples of input operations and displays to explain the tax calculation function of the calculator according to the embodiment. 11A to 11C are diagrams showing specific examples of input operations and displays to explain the tax calculation function of the calculator according to the embodiment. 11A to 11C are diagrams showing specific examples of input operations and displays to explain the tax calculation function of the calculator according to the embodiment. FIG. 13 is a diagram showing an example of a voucher format used in a retail store in India.

The following describes an embodiment of the present invention with reference to the drawings.

Figure 1 is a front view showing the external configuration of a tax calculator according to this embodiment. In this embodiment, the tax calculator is realized as a calculator 10 dedicated to calculations.

The tax calculator can be configured as a calculator 10, or as a personal computer with a calculation function (implemented with a calculation program), a tablet computer, a smartphone, a mobile phone, a touch-panel PDA (personal digital assistant), an electronic book, a portable game machine, etc. Tax calculators that do not have physical keys (buttons) like the calculator 10 display a software keyboard similar to the keys of the calculator 10, and perform calculations in response to key operations on this software keyboard.

The calculator 10 in this embodiment is provided with a tax calculation function that calculates tax using multiple tax rates, for example, five different tax rates. For example, five different tax rates (0%, 5%, 12%, 18%, and 28%) are used for consumption tax in India. Therefore, the calculator 10 in this embodiment is suitable for calculating taxes in India and other countries that include five or fewer different consumption taxes.

On the front of the housing of calculator 10, there are provided key input section 11 including multiple keys, display section 12, and solar panel 13. Key input section 11 is provided with numeric keys, arithmetic keys, tax calculation function keys, function keys, and calculation check function keys. The numeric keys include multiple keys corresponding to each of the numbers [00], [0] to [9], for example. The arithmetic keys include multiple keys corresponding to each of the four arithmetic operations used in normal calculations, for example, [+] (addition) key 11h1, [-] (subtraction) key 11h2, [x] (multiplication) key 11h3, [÷] (division) key 11h4, and [=] (operation execution) key 11h0.

The tax calculation function keys include a tax calculation key ([GST+n(TAX-n)]) 11b, a tax calculation total key ([GST GT(GT)]) 11c, and a tax calculation mode switching key ([GST+/TAX-]) 11d. Here, GST is an abbreviation for "Goods and Service Tax", which means the consumption tax in India. The characters in [ ] (excluding the characters in ( )) indicate the characters printed on the key top of each tax calculation key 11b, and the characters in ( ) within [ ] are for convenience the characters printed on the front of the case of the calculator 10. In this specification, the same notation is used not only for the tax calculation key 11b.

The tax calculation key ([GST+n(TAX-n)]) 11b includes a tax 0 calculation key ([GST+0(TAX-0)]) 11b0, a tax 1 calculation key ([GST+1(TAX-1)]) 11b1, a tax 2 calculation key ([GST+2(TAX-2)]) 11b2, a tax 3 calculation key ([GST+3(TAX-3)]) 11b3 and a tax 4 calculation key ([GST+4(TAX-4)]) 11b4. The tax 0 calculation key ([GST+0(TAX-0)]) 11b0 is operated to input an instruction to perform a tax calculation using tax rate 0. Similarly, the tax 1 calculation key ([GST+1(TAX-1)]) 11b1, tax 2 calculation key ([GST+2(TAX-2)]) 11b2, tax 3 calculation key ([GST+3(TAX-3)]) 11b3, and tax 4 calculation key ([GST+4(TAX-4)]) 11b4 are operated to input instructions to execute tax calculations using tax rate 1, tax rate 2, tax rate 3, and tax rate 4, respectively. In this specification, when expressing the tax calculation key ([GST+n(TAX-n)]) 11b in this way, "n" is used instead of each number from 0 to 4. In this specification, not limited to the tax calculation key 11b, when there is no particular restriction on which number "n" can take (an integer from 0 to 4), "n" is used for convenience instead of a specific number.

One tax calculation key 11b (tax n calculation keys 11b0-11b4) serves as both the tax-inclusive calculation key [GST+n] and the tax-exclusive calculation key [TAX-n]. The tax calculation key 11b (tax n calculation keys 11b0-11b4) is used as either the tax-inclusive calculation key [GST+n] or the tax-exclusive calculation key [TAX-n] depending on the tax calculation mode that is switched in response to the operation of the tax calculation mode switching key ([GST+/TAX-]) 11d. By using one tax calculation key 11b both as the tax-inclusive calculation key [GST+n] and the tax-exclusive calculation key [TAX-n], the limited area on the front of the case is effectively utilized to provide keys that can execute tax-inclusive calculation processing and tax-exclusive calculation processing corresponding to each of multiple (five) tax rates.

The tax rates (tax rate 0 to tax rate 4) assigned to the tax calculation keys 11b (tax n calculation keys 11b0 to 11b4) are preset when the calculator 10 is shipped from the factory. For example, five tax rates (0%, 5%, 12%, 18%, 28%) are set to the tax n calculation keys 11b0 to 11b4, respectively, to accommodate use in India. The tax rates (tax rate 0 to tax rate 4) assigned to the tax n calculation keys 11b0 to 11b4 can also be set arbitrarily by the user.

The tax calculation total key ([GST GT (GT)]) 11c serves both as a grand total key ([GT] key) for displaying the total for normal calculations (basic calculations) such as arithmetic operations and constant calculations, and as a GST grand total key ([GST GT] key) for displaying the total for the tax calculation results. When the tax calculation total key 11c functions as a GST grand total key, the tax calculation is performed and the processing mode of the calculator 10 transitions to the tax total recall mode (GST GT recall mode). On the other hand, when the tax calculation total key 11c functions as a grand total key, the processing mode of the calculator 10 does not transition in particular, but simply calls up the values stored in the total memory area 22h and displays them on the display unit 12. These processes will be explained in detail later using FIG. 4.

The tax calculation total key 11c functions as either a grand total key ([GT] key) or a GST grand total key ([GST GT] key), depending on the operating state immediately before the tax calculation total key 11c was operated. Specifically, when the processing mode of the calculator 10 is not the tax total recall mode, for example, immediately after a tax calculation is performed by operating the tax calculation key 11b, that is, after the tax calculation is performed and the result of the tax calculation is being displayed on the display unit 12, if the tax calculation total key 11c is pressed, the tax calculation key 11b functions as a GST grand total key ([GST GT] key) that displays the grand total of the tax calculation results. Also, when the processing mode of the calculator 10 is not the tax total recall mode, for example, immediately after a normal calculation is performed by operating the calculation execution key ([=] key) 11h0, that is, after the normal calculation is performed, while the result of the normal calculation is being displayed on the display unit 12, if the tax calculation total key 11c is pressed, that is, not immediately after a tax calculation is performed by operating the tax calculation key 11b, the tax calculation key 11b functions as a grand total key ([GT] key) for displaying the total sum for the normal calculation (basic calculation). Note that the time for which the tax calculation total key 11c is pressed here is shorter than a predetermined arbitrary time, and is shorter than the "long press" described below. Also, for the sake of convenience, pressing for a short time is described in this specification as a "short press" or a normal pressing operation.

Furthermore, when the tax calculation total key 11c is operated (for example, pressed and held) differently from the normal pressing operation, it functions as the opposite key to the above. That is, for example, when the tax calculation total key 11c is pressed and held immediately after the tax calculation is performed by operating the tax calculation key 11b, the tax calculation total key 11c functions as the grand total key ([GT] key). Also, for example, when the tax calculation total key 11c is pressed and held immediately after the normal calculation is performed by operating the calculation execution key ([=] key) 11h0, that is, not immediately after the tax calculation is performed by operating the tax calculation key 11b, the tax calculation total key 11c functions as the GST grand total key ([GST GT] key). Note that the different operation from the normal operation of the tax calculation total key 11c can be an operation other than the above-mentioned long pressing operation (operation of continuing the pressed state for more than the above-mentioned predetermined arbitrary time).

The function keys include, for example, an all clear key ([AC] key 11a), a clear key ([C] key), multiple memory keys ([MRC] [M-] [M+]), a root key ([√] key), and a [%] key 11g. The [%] key 11g is used for percentage calculations, and is also used to start a tax rate setting process for setting the tax rates corresponding to each of the tax calculation keys 11b (tax n calculation keys 11b0 to 11b4) to values entered by key operation.

The calculation check function keys are used in the calculation check function to check/correct the contents of a previously executed calculation. The calculation check function keys include a check key (CHECK BACK key 11e, CHECK FORWARD key 11f) and a correction key (CORRECT key) 11k. The CHECK BACK key 11e and the CHECK FORWARD key 11f are used to switch the display of the contents (calculation data) of a previously executed calculation by step. When the CHECK BACK key 11e is operated, the display switches to the calculation data of the step with the fewer steps, and when the CHECK FORWARD key 11f is operated, the display switches to the calculation data of the step with the greater number of steps. Note that one step is the unit of "numeral input + function" entered for the calculation. The "function" stores the code of the key operated for arithmetic operations, calculation with tax, calculation without tax, etc. The correction key 11k is a key for instructing correction of the contents of the calculation ("numerals + function") displayed by operating the [CHECK BACK] key 11e or the [CHECK FORWARD] key 11f. By inputting the corrected contents of the calculation after operating the correction key 11k, the previously entered displayed calculation data can be corrected.

The round selector 11y sets the calculation method for rounding. For example, the "F" setting specifies that the maximum number of digits that can be displayed, including the decimal point, are to be displayed on the display unit 12. The "CUT" setting specifies that the digits specified by the decimal point selector 11z are to be rounded down. The "UP" setting specifies that the digits specified by the decimal point selector 11z are to be rounded up. The "5/4" setting specifies that the digits specified by the decimal point selector 11z are to be rounded up or down. The decimal point selector 11z sets how many digits after the decimal point the display unit 12 should display. The "ADD2" setting specifies that the decimal point is set to a specified number of digits for the input numeric value.

The display unit 12 is a dot-matrix type liquid crystal display unit. The display unit 12 displays numerical values input by operating the keys of the key input unit 11. The display unit 12 displays numerical values for a limited number of rows (for example, one row). In addition, a status display area provided along the side of the display unit 12 displays characters and symbols indicating the calculation mode being set and various setting states. For example, the status display area displays the number of steps 12a, tax calculation mode symbol 12b, tax calculation key symbol 12c, tax total recall mode symbol 12d, grand total display symbol 12e, memory symbol 12f, etc. In FIG. 1, all displayable symbols are conveniently shown on the same screen to explain the status display area, but such a large number of symbols are not necessarily displayed simultaneously on the same screen in any state that the calculator 10 can be in.

The step number 12a indicates the position of the step currently being displayed, with one step being the "number input + function" input by operating the keys on the key input unit 11. The tax calculation mode symbol 12b indicates the current tax calculation mode, and displays, for example, [GST+] in the tax-inclusive calculation mode, which performs a tax-inclusive calculation, and [TAX-] in the tax-exclusive calculation mode, which performs a tax-exclusive calculation.

The tax calculation key symbol 12c is a symbol that indicates the tax rate used in the tax calculation and whether the calculation is tax-inclusive or tax-exclusive when a tax calculation is performed by operating the tax calculation key 11b. When the tax calculation key 11b is used as the tax-inclusive calculation key [GST+n], one of [GST+0], [GST+1], [GST+2], [GST+3], or [GST+4] corresponding to the tax rates 0 to 4 is displayed. When the tax calculation key 11b is used as the tax-exclusive calculation key [TAX-n], one of [TAX-0], [TAX-1], [TAX-2], [TAX-3], or [TAX-4] corresponding to the tax rates 0 to 4 is displayed.

The tax total recall mode symbol 12d is a symbol indicating that the mode has been switched to the tax total recall mode (GST GT recall mode) by operating the tax calculation total key ([GST GT (GT)]) 11c, and for example, "RCL" is displayed. In the tax total recall mode, the total including tax, the total excluding tax, and the total tax amount can be switched to be displayed as the total of the tax calculations calculated at each tax rate (tax rates 0 to 4) in response to key operation on the tax calculation total key 11c. Also, in the tax total recall mode, the tax rate to be displayed (tax rates 0 to 4) can be specified by key operation on the tax calculation key 11b, and the total including tax, the total excluding tax, and the total tax amount can be switched to be displayed as the total of the tax calculations for the specified tax rate.

The grand total display symbol 12e is a symbol that indicates that the result of a normal calculation performed in response to the operation of the calculation execution key [=] 11h0 is stored in the total memory area 22h, and for example, "GT" is displayed. The memory symbol 12f is a symbol that indicates that a numerical value has been stored by the memory function in response to the operation of the memory keys ([M-] [M+]).

The solar panel 13 generates electricity when the illuminance of the ambient light when the calculator 10 is being used is relatively bright. When generating electricity, the solar panel 13 functions as the power supply unit 26 (shown in FIG. 2) of the calculator 10 and supplies power to each part of the calculator 10. When the solar panel 13 is not generating electricity, power is supplied to each part of the calculator 10 from a primary battery that serves as the power supply unit 26 provided separately in the calculator 10.

Figure 2 is a block diagram showing the configuration of the electronic circuit of the calculator 10 in this embodiment. The electronic circuit of the calculator 10 includes multiple units that constitute a computer, including a CPU 21.

The CPU 21 controls the operation of each part of the circuit by executing the calculation processing program 22a stored in the memory 22. When an input operation is performed on the key input unit 11, the CPU 21 detects the key that was input by the key input signal from the key input unit 11, and executes various calculation processes according to each detected key. The calculator 10 realizes calculation processes including the processing by the calculation function described in the operation explanation below by the CPU 21 controlling the operation of each part of the circuit according to the instructions written in the calculation processing program 22a and by the software and hardware operating in cooperation with each other.

The calculation processing program 22a may be stored in advance in the memory 22, or may be read from an external recording medium 23 such as a memory card via the recording medium reading unit 24, or may be downloaded from a server 30 on a communication network N (including the Internet, etc.) via the communication unit 25.

In addition to storing the calculation processing program 22a, the memory 22 has areas for storing the calculation results of the tax calculation (tax memory), total memory area 22h, tax total recall mode area 22k, tax calculation mode area 22m, buffer memory area 22n, display memory area 22p, tax rate storage area 22r, and other areas for storing various data. The tax memory (first memory) includes tax rate 0 total memory area 22b, tax rate 1 total memory area 22c, tax rate 2 total memory area 22d, tax rate 3 total memory area 22e, tax rate 4 total memory area 22f, and tax total memory area 22g. In the following explanation, the tax rate 0 total memory area 22b, tax rate 1 total memory area 22c, tax rate 2 total memory area 22d, tax rate 3 total memory area 22e, and tax rate 4 total memory area 22f may be collectively referred to as tax rate-specific tax total memory areas 22b to 22f.

The tax rate 0 total memory area 22b is an area for storing data calculated by a tax calculation based on a tax rate of 0. The tax rate 0 total memory area 22b stores a numerical value based on the result of a tax-inclusive calculation with a tax rate of 0. Specifically, the totals of the tax-inclusive amount (0th tax-inclusive amount), tax amount (0th tax amount), and tax-exclusive amount (0th tax-exclusive amount) resulting from a tax-inclusive calculation with a tax rate of 0 performed one or more times since the last input operation of the [AC] key 11a are stored as the 0th tax-inclusive total amount, the 0th tax-exclusive total amount, and the 0th tax total amount, respectively.

The tax rate 1 total memory area 22c, the tax rate 2 total memory area 22d, the tax rate 3 total memory area 22e, and the tax rate 4 total memory area 22f are areas for storing data calculated by tax calculations based on each of the tax rates 1 to 4, similar to the tax rate 0 total memory area 22b described above. A detailed explanation will be omitted.

The tax total memory area 22g is an area for storing data indicating the sum of the numerical values calculated by tax calculation based on all tax rates 0 to 4. In response to the input operation of the tax calculation total key 11c, the tax total memory area 22g stores the total amount including tax obtained by adding up the 0th to 4th tax-inclusive total amounts, the total amount excluding tax corresponding to the total amount including tax, and the total amount including tax corresponding to the total amount including tax.

The total memory area 22h is an area for storing data indicating the sum of the numerical values calculated by normal calculation (second memory). The result of normal calculation is calculated in response to the operation of the calculation execution key [=] 11h0, and the numerical value as the calculation result is added to the numerical value stored in the total memory area 22h.

In the tax total recall mode area 22k, the tax total recall mode flag, which indicates whether the calculator is in recall mode or not, is set to the on or off state in response to an input operation on the tax calculation total key 11c. The tax total recall mode is turned on when the tax calculation total key 11c is pressed immediately after a tax calculation performed by operating the tax calculation key 11b, or when the tax calculation total key 11c is pressed and held immediately after a normal calculation (transition to tax total recall mode). The tax total recall mode is also turned off when, for example, the [AC] key 11a is operated as a predetermined instruction to turn off the tax total recall mode. Note that the switching of the tax total recall mode on/off is not limited to the operation of the tax calculation total key 11c and the [AC] key 11a. For example, the tax total recall mode may be switched on/off in response to another key operation or in response to the processing result of the calculator 10.

When the tax total recall mode is on, the display can be switched between the tax-inclusive total amount, tax-exclusive total amount, and tax total amount stored in the tax total memory area 22g each time the tax calculation total key 11c is operated (pressed). Also, when the tax total recall mode is on, the display can be switched between the tax-inclusive total amount, tax-exclusive total amount, and tax total amount stored in the tax-rate-specific tax total memory areas 22b to 22f each time the tax calculation key 11b (tax n calculation keys 11b0 to 11b4) is operated (pressed).

The on state of the tax total recall mode is maintained even when input is made using the numeric keys and calculation keys of the key input unit 11. Therefore, it is possible to perform normal calculations using the numeric keys and calculation keys while displaying and checking the result of the tax calculation by inputting the tax calculation total key 11c or the tax calculation key 11b (11b0 to 11b4). In normal calculations when the tax total recall mode is on, the numeric value resulting from the tax calculation is displayed on the display unit 12, and arithmetic operations can be performed on the input numbers displayed on the display unit 12.

The tax calculation mode area 22m stores tax calculation mode data indicating whether the mode is tax-inclusive calculation mode or tax-exclusive calculation mode, which can be switched in response to an input operation on the tax calculation mode switching key 11d.

The buffer memory area 22n stores the input number that is paired with the last input function to form a unit. The display memory area 22p stores the value currently displayed on the display unit 12. For example, if the number "100" is input by operating the numeric keys and the tax 1 calculation key ([GST+1(TAX-1)]) 11b1 is operated in sequence as the function, the buffer memory area 22n stores the number "100" as the input number, and the display memory area 22p stores the number "105" that is also displayed on the display unit 12 as the result of the tax-inclusive calculation of tax rate 1 (assuming tax rate 1 is 5%). In this way, the values stored in the buffer memory area 22n and the display memory area 22p are overwritten and updated in sequence according to the most recent input operation.

The tax rate memory area 22r stores a numerical value indicating the tax rate 0 to 4 set for each of the tax calculation keys 11b (tax n calculation keys 11b0 to 11b4). For example, five tax rates (0%, 5%, 12%, 18%, 28%) are set for the tax n calculation keys 11b0 to 11b4 at the time of factory shipment to accommodate use in India. In this case, the tax rate memory area 22e stores the numerical values "0", "5", "12", "18", and "28" for the tax rates 0 to 4 corresponding to the tax n calculation keys 11b0 to 11b4.

Next, the operation of the calculator 10 in this embodiment will be described. Figures 3, 4, 5, 6, and 7 are flow charts for explaining the operation of the tax calculation function of the calculator 10 in this embodiment. Figures 8, 9, 10, and 11 are diagrams showing specific examples of input operations and displays for explaining the tax calculation function of the calculator 10 in this embodiment.

In the following explanation, for the sake of convenience, the tax rate 1 corresponding to the tax 1 calculation key ([GST+1(TAX-1)]) 11b1 is set to 5%.

First, the user operates (presses) the [AC] key 11a to clear the display and memory contents before starting calculation. When the [AC] key 11a is operated (step A9: Yes), the CPU 21 clears all of the tax rate-specific tax total memory areas 22b to 22f, the tax total memory area 22g, the total memory area 22h, the buffer memory area 22n, and the display memory area 22p in the memory 22 (step A12). The CPU 21 also turns off the tax total recall mode flag stored in the tax total recall mode area 22k (step A13). When the [AC] key 11a is operated in a state where a numerical value such as a previous tax calculation result is displayed, the CPU 21 clears the previously displayed numerical value and displays "0". When the [AC] key 11a is operated in a state where the previous symbol is displayed in the status display area of the display unit 12, the CPU 21 clears the previously displayed symbol and makes it invisible.

If an input operation to the tax calculation key 11b (any of the tax n calculation keys 11b0 to 11b4) is detected immediately after the input operation of the [AC] key 11a (step A19: Yes), A117: Yes), the CPU 21 reads the tax rate set for any of the tax n calculation keys 11b0 to 11b4 for which the input operation was performed from the tax rate storage area 22r of the memory 22 and displays it on the display unit 12 (step A118). For example, if the tax 1 calculation key 11b1 is operated immediately after the input operation of the [AC] key 11a, the CPU 21 reads the number indicating tax rate 1 (5%) set for the tax 1 calculation key 11b1 from the tax rate storage area 22r and displays "5" on the display unit 12.

If an input operation is detected for the tax calculation key 11b (any of the tax n calculation keys 11b0 to 11b4) without any other key operation being performed other than the tax calculation key 11b (step A19: Yes, A117: Yes), that is, as long as the key operation of the tax calculation key 11b is continuous, the CPU 21 will read out from the memory 22 one of the tax rates 0 to 4 set for the tax calculation key 11b for which the input operation was performed, in the same manner as described above, and display it on the display unit 12 (step A118).

That is, if the [AC] key 11a is input immediately after the input operation, the tax calculation key 11b (tax n calculation key 11b0 to 11b4) can be operated continuously to continuously switch and display the tax rates 0 to 4 set for each tax calculation key 11b. Note that if only the tax calculation key 11b is input two or more times in succession after the last [AC] key 11a is input, the second and subsequent input operations of the tax calculation key 11b are not strictly speaking performed immediately after the [AC] key 11a input operation, but in this specification, such input operations are also considered to have been performed immediately after the [AC] key 11a input operation. Also, if an input operation other than the tax calculation key 11b is performed even once after the last [AC] key 11a input operation, the subsequent input operations of the tax calculation key 11b are considered to have not been performed immediately after the [AC] key 11a input operation.

Next, when the user operates a numeric key to input a numerical value to be calculated (step A10: Yes), the CPU 21 inputs a numerical value (numeric code) corresponding to the numeric key operated, stores the input numerical value in the display memory area 22p, and displays it on the display unit 12 (step A15).

Next, when an operation key is operated (step A11: Yes), the CPU 21 inputs an operation (operation code) corresponding to the operation key that was operated, and displays the operation (symbol) symbol of the input operation in the status display area of the display unit 12 (step A16).

The CPU 21 also executes a calculation based on the input operation code and the input numeric code, stores the numerical result in the display memory area 22p, and displays it on the display unit 12. In the same manner, the input of the numeric code and the operation code is repeated, and the CPU 21 sequentially stores the input numeric code and operation code. When the operation execution key "=" (equal) 11h0 is operated by the user (step A17: Yes), the CPU 21 inputs an operation code corresponding to the input operation operation key ("=" key) 11h0, executes a calculation corresponding to the numeric code and operation code input up to that point, stores the numerical result of the calculation in the display memory area 22p, and displays it on the display unit 12. The CPU 21 also stores the numerical value as the result of the normal calculation corresponding to the numeric code and the operation code in the total memory area 22h (step A18). If a numerical value has already been stored in the total memory area 22h, the CPU 21 adds the numerical value as the result of the normal calculation to the numerical value previously stored, and stores the result in the memory 22. If the calculation execution key "=" (equal) 11h0 is not operated by the user (step A17: No), the CPU 21 returns to the input operation standby state.

If an input operation of the tax calculation key 11b is detected with a number displayed on the display unit 12 other than immediately after the input operation of the [AC] key 11a (step A19: Yes → A117: No), the CPU 21 performs tax calculation on the number (number entered) displayed on the display unit 12, i.e., the number stored in the display memory area 22p, using the tax rate set for one of the tax n calculation keys 11b0 to 11b4 where the input operation was performed. Note that the numbers subject to tax calculation are not limited to numbers displayed by normal calculation, but can simply be numbers input by input operation of the numeric keys.

The tax calculation key 11b (each of the tax n calculation keys 11b0 to 11b4) serves both as a key for performing tax-inclusive calculation and a key for performing tax-exclusive calculation. When the tax calculation key 11b is operated, the CPU 21 refers to the tax calculation mode area 22m to determine whether the current tax calculation mode is the tax-inclusive calculation mode or the tax-exclusive calculation mode. If the current tax calculation mode is the tax-inclusive calculation mode (step A110, tax-inclusive), the CPU 21 executes a tax-inclusive calculation process that displays the tax calculation result in response to key operation (step A111). If the current tax calculation mode is the tax-exclusive calculation mode (step A110, tax-exclusive), the CPU 21 executes a tax-exclusive calculation process that displays the tax calculation result in response to key operation (step A112).

The tax calculation mode can be switched by operating the tax calculation mode switching key 11d. When the CPU 21 detects the operation of the tax calculation mode switching key 11d (step A14: Yes), it refers to the tax calculation mode area 22m and determines whether the current tax calculation mode is the tax-inclusive calculation mode or the tax-exclusive calculation mode.

If the current tax calculation mode is the tax-inclusive calculation mode (step A113, tax included), the CPU 21 stores tax calculation mode data indicating the tax-exclusive calculation mode in the tax calculation mode area 22m (step A114). The CPU 21 also displays the tax calculation mode symbol 12b ([TAX-]) indicating the tax-exclusive calculation mode in the status display area of the display unit 12 (step A116).

On the other hand, if the current tax calculation mode is the tax-exclusive calculation mode (step A113, tax-exclusive), the CPU 21 stores tax calculation mode data indicating the tax-inclusive calculation mode in the tax calculation mode area 22m (step A115). The CPU 21 also displays the tax calculation mode symbol 12b ([GST+]) indicating the tax-inclusive calculation mode in the status display area of the display unit 12 (step A116).

When the tax calculation mode is switched in response to the operation of the tax calculation mode switching key 11d, the CPU 21 maintains the calculation results (tax-excluded total amount, tax-included total amount, tax total amount) stored in the tax-rate-specific tax total memory areas 22b to 22f. Therefore, when performing a mixture of tax-inclusive and tax-excluded calculations, even if the tax calculation mode is switched, the intermediate calculation results are retained.

Next, the tax-inclusive calculation process in this embodiment will be explained with reference to the flowchart shown in FIG.

When the tax 0 calculation key 11b0 is operated (step B1: Yes), the CPU 21 executes the tax rate 0 calculation process using the tax rate 0 set for the tax 0 calculation key 11b0 (step B6). Similarly, when the tax 1 calculation key 11b1 is operated (step B2: Yes), the CPU 21 executes the tax rate 1 calculation process (step B10), when the tax 2 calculation key 11b2 is operated (step B3: Yes), the CPU 21 executes the tax rate 2 calculation process (step B3), when the tax 3 calculation key 11b3 is operated (step B4: Yes), the CPU 21 executes the tax rate 3 calculation process (step B8), and when the tax 4 calculation key 11b4 is operated (step B5: Yes), the CPU 21 executes the tax rate 4 calculation process (step B9).

The tax rate 0 calculation process, tax rate 1 calculation process, tax rate 2 calculation process, tax rate 3 calculation process, and tax rate 4 calculation process all execute essentially the same process. Here, we will explain the tax rate 1 calculation process, and will omit detailed explanations of the other calculation processes.

FIG. 6 is a flowchart for explaining the tax rate 1 calculation process of the tax-inclusive calculation process in this embodiment.
When the CPU 21 detects the input operation of the tax 1 calculation key 11b1 (step B2: Yes), it judges whether the tax total recall mode is OFF by referring to the tax total recall mode area 22k. The tax total recall mode is changed to ON by the operation of the tax calculation total key 11c. The change of the tax total recall mode to ON is executed in step A28 described later.

Here, if the tax total recall mode is off (step B21: Yes), the CPU 21 reads out the numerical value (number of entries) stored in the display memory area 22p, calculates the tax-inclusive amount and tax amount based on the tax-exclusive amount and tax rate 1 ("5%), which is the tax rate according to the tax calculation key 11b that was entered, and stores the calculated tax-inclusive amount and tax amount together with the tax-exclusive amount indicated by the displayed numerical value in the tax rate 1 total memory area 22c (step B22). The CPU 21 also stores the numerical value used for the tax-inclusive calculation stored in the display memory area 22p in the buffer memory area 22n, and stores the numerical value of the tax-inclusive amount calculated based on tax rate 1 in the display memory area 22p (step B23). Furthermore, the CPU 21 displays the tax-inclusive amount calculated based on tax rate 1 on the display unit 12 (step B24).

If step B22 has been executed one or more times in the period from the last input operation of the [AC] key 11a until the current execution of step B22, the tax-excluded amount or its total amount, the tax-inclusive amount or its total amount, and the tax amount or its total amount calculated in the one or more previously executed steps of step B22 have already been stored in the tax rate 1 total memory area 22c before the current execution of step B22. Therefore, when step B22 is executed, if the tax-excluded amount or its total amount, the tax-inclusive amount or its total amount, and the tax amount or its total amount have already been stored in the tax rate 1 total memory area 22c, the tax-excluded amount, the tax-inclusive amount, and the tax amount calculated when step B22 was executed this time are added to the stored tax-excluded amount or its total amount, the tax-inclusive amount or its total amount, and the tax amount or its total amount, respectively. In this way, the tax rate 1 total memory area 22c stores the totals of the tax-excluded amount, tax-inclusive amount, and tax amount obtained by one or more tax-inclusive calculations (step B22) for all tax rate 1 performed after the last input operation of the [AC] key 11a.

In this way, the CPU 21 can continuously instruct the calculation including tax for multiple numerical values (set values) in response to an input operation on the tax 1 calculation key 11b1.

In addition, when the tax-inclusive amount is displayed, the display can be switched between the tax-inclusive amount, the tax-exclusive amount, and the tax amount by subsequently operating the tax 1 calculation key 11b1 that was operated to instruct the tax calculation. For example, when the tax-inclusive amount calculated based on tax rate 1 is displayed (step B24), if the tax 1 calculation key 11b1 is operated (step B25: Yes), the CPU 21 reads out the numerical value (number entered) stored in the buffer memory area 22n and displays it as the tax-exclusive amount (step B26). As described above, at this time, that is, immediately after the tax-inclusive calculation (immediately after steps B22 and B23 are executed), the tax-exclusive amount numerical value used in the tax-inclusive calculation is stored in the buffer memory area 22n. Also, when the tax-excluded amount is displayed (step B26), if the tax 1 calculation key 11b1 is operated (step B27: Yes), the CPU 21 reads out the numerical value (tax-excluded amount) stored in the buffer memory area 22n, recalculates the tax amount based on the read numerical value and tax rate 1, and displays the numerical value on the display unit 12 (step B28). Furthermore, if the tax 1 calculation key 11b1 is subsequently operated (step B29: Yes), the CPU 21 reads out the numerical value (tax-excluded amount) stored in the buffer memory area 22n, recalculates the tax-inclusive amount based on the read numerical value and tax rate 1, and displays the numerical value on the display unit 12 (step B24).

In this way, the calculator 10 can calculate the tax-inclusive amount in response to the operation of the tax 1 calculation key 11b1, and then switch between displaying the tax-inclusive amount, tax-exclusive amount, and tax amount in sequence with each operation of the tax 1 calculation key 11b1. This allows the user to easily check the tax-inclusive amount, tax-exclusive amount, and tax amount.

On the other hand, if the tax total recall mode is on (step B21: No), the CPU 21 reads out the first tax-inclusive total amount, which indicates the total tax-inclusive amount calculated for at least one numerical value using tax rate 1, from the tax rate 1 total memory area 22c and displays it on the display unit 12 (step B30). The transition of the tax total recall mode to the on state will be described later.

Furthermore, when the tax 1 calculation key 11b1 is operated while the first tax-inclusive total amount is displayed (step B31, Yes), the CPU 21 reads out the first tax-excluded total amount (total of amounts excluding tax) corresponding to the first tax-inclusive total amount from the tax rate 1 total memory area 22c and displays it (step B32). Furthermore, when the tax 1 calculation key 11b1 is operated while the first tax-excluded total amount is displayed (step B33: Yes), the CPU 21 reads out the first tax total amount (total of taxes) corresponding to the first tax-inclusive total amount from the tax rate 1 total memory area 22c and displays it (step B34). Furthermore, when the tax 1 calculation key 11b1 is operated while the first tax total amount is displayed (step B35: Yes), the CPU 21 reads out the first tax-inclusive total amount from the tax rate 1 total memory area 22c and displays it (step B30).

In other words, when the tax total recall mode is on, the calculator 10 can sequentially switch between displaying the first tax-inclusive total, the first tax-exclusive total, and the first tax total calculated based on tax rate 1, each time the tax 1 calculation key 11b1 is operated. Therefore, after calculating taxes on multiple numerical values using tax rate 1, the first tax-inclusive total, the first tax-exclusive total, and the first tax total can be easily confirmed as the results of multiple tax calculations using tax rate 1.

When the tax total recall mode is on (step B21: No), if the CPU 21 detects that one of the multiple tax calculation keys 11b (11b0 to 11b4) has been operated (step B31: No, step B33: No, step B35: No), it moves to the calculation process corresponding to the operated tax calculation key 11b (steps B36 to B39) and executes the same process as steps B21 to B35 described above.

For example, when the CPU 21 detects that the tax 0 calculation key 11b0 is operated while the first tax-inclusive total amount, the first tax-exclusive total amount, or the first tax-exclusive total amount is displayed (step B31: No, step B33: No, step B35: No → step B36: Yes), the CPU 21 proceeds to the tax rate 0 calculation process (step B6). In this case, since the tax total recall mode is on, the CPU 21 reads out the 0th tax-inclusive total amount (total of tax-inclusive amounts with tax rate 0) from the tax rate 0 total memory area 22b and displays it, as in the above-mentioned step B30. Also, when the tax 0 calculation key 11b1 is operated while the 0th tax-inclusive total amount is displayed, the CPU 21 reads out the 0th tax-exclusive total amount (total of tax-exclusive amounts with tax rate 0) from the tax rate 1 total memory area 22c and displays it, as in the above-mentioned step B32. Furthermore, when the 0th tax-excluded total amount is displayed and the 0th tax calculation key 11b0 is operated, the CPU 21 reads out the 0th tax total amount (the sum of the taxes with a tax rate of 0) from the 0th tax rate total memory area 22b and displays it, just as in step B34 described above.

Similarly, when the CPU 21 detects that the tax 2 calculation key 11b2 has been operated (step B37: Yes), it transitions to the tax rate 2 calculation process (step B7) and executes the same process as described above. When the CPU 21 detects that the tax 3 calculation key 11b3 has been operated (step B38: Yes), it transitions to the tax rate 3 calculation process (step B8), and when the CPU 21 detects that the tax 4 calculation key 11b4 has been operated (step B27: Yes), it transitions to the tax rate 4 calculation process (step B9), and executes the same process as described above. When the CPU 21 detects that the tax calculation total key 11c has been operated (step B40: Yes), it transitions to the process of displaying the total amount including tax, the total amount excluding tax, and the total amount of tax calculated at each tax rate (processing of steps A29 to A214 described later). When the CPU 21 does not detect that the tax calculation total key 11c has been operated (step B40: No), it returns to the standby state for input operation. In addition, when operation of the tax 1 calculation key 11b1 is detected in the tax rate 0 calculation process, tax rate 2 calculation process, tax rate 3 calculation process, and tax rate 4 calculation process, the process transitions to the tax rate 1 calculation process (step B10), as shown in FIG. 5.

In each calculation process for tax rates 0 to 4, while the tax total recall mode is on, the tax calculation key 11b corresponding to each of the other tax rates can be operated to switch to the other calculation process corresponding to the operated tax calculation key 11b, and the total amount including tax, the total amount excluding tax, and the total tax amount calculated based on the tax rate corresponding to the other calculation process can be displayed.

Therefore, when the tax total recall mode is on, by selecting one of the multiple tax calculation keys 11b (11b0 to 11b4), the total amount including tax, the total amount excluding tax, and the total tax amount calculated using the tax rate corresponding to the operated tax calculation key 11b can be easily confirmed.

Next, the tax-excluded calculation process in this embodiment will be described with reference to the flowchart shown in FIG. 7. Here, the case where the tax 1 calculation key 11b1 is operated will be described. When the tax 0 calculation key 11b0, tax 2 calculation key 11b2, tax 3 calculation key 11b3, and tax 4 calculation key 11b4 are operated, the same process as when the tax 1 calculation key 11b1 is operated is executed, so detailed explanations will be omitted.

When the CPU 21 detects that the tax 1 calculation key 11b1 has been operated, the CPU 21 reads out the numerical value (number entered) stored in the display memory area 22p, and calculates the tax-excluded amount based on the tax-excluded amount and tax rate 1 ("5%"), which is the tax rate corresponding to the tax calculation key 11b that was operated (step C13). The CPU 21 also stores the numerical value used for the tax-excluded calculation stored in the display memory area 22p in the buffer memory area 22n, and stores the tax-excluded amount calculated based on tax rate 1 in the display memory area 22p (step C2). The CPU 21 also displays the tax-excluded amount calculated based on tax rate 1 on the display unit 12 (step C3).

When the tax-excluded amount is displayed, the display can be switched between the tax-excluded amount and the tax amount by subsequently operating the tax 1 calculation key 11b1 that was operated to instruct tax calculation. For example, when the tax-excluded amount calculated based on tax rate 1 is displayed (step C3), if the tax 1 calculation key 11b1 is operated (step C4: Yes), the CPU 21 reads out the numerical value (tax-inclusive amount) stored in the buffer memory area 22n, recalculates the tax amount based on the read numerical value and tax rate 1, and displays the numerical value on the display unit 12 (step C5). Furthermore, if the tax 1 calculation key 11b1 is subsequently operated (step C6: Yes), the CPU 21 reads out the numerical value (tax-excluded amount) stored in the buffer memory area 22n, and displays the read numerical value on the display unit 12 (step C3).

In this way, the calculator 10 can calculate the tax-excluded amount in response to the operation of the tax 1 calculation key 11b1, and then alternate between displaying the tax-excluded amount and the tax amount with each operation of the tax 1 calculation key 11b1. This allows the tax-excluded amount and the tax amount to be easily confirmed.

In the tax-excluded calculation process, the tax-inclusive amount is not displayed even if the tax 1 calculation key 11b1 is operated. In the tax-included calculation process, the calculation result calculated in response to the operation of the tax calculation key 11b is reflected (added) to the tax rate 1 total memory area 22c, but in the tax-excluded calculation process, the calculation result is not reflected in the tax rate 1 total memory area 22c.

On the other hand, in step C3, the figure (tax-excluded amount) calculated by the tax-excluded calculation can be used as a preset quantity to subsequently carry out a tax-inclusive calculation using a different tax rate or a regular calculation.

For example, in markets such as India that use multiple consumption tax rates, prices are listed as MRP (short for Maximum Retail Price, which is retail price = tax-inclusive amount). Therefore, when calculating the tax-inclusive amount using a different tax rate based on the tax-inclusive amount, it is necessary to convert the tax-inclusive amount back to the tax-exclusive amount, then perform a new tax-inclusive calculation according to the different tax rate to obtain the tax-exclusive amount, tax-inclusive amount, and tax amount.

In the present embodiment, when the calculator 10 is performing tax-inclusive calculations (tax-exclusive total, tax-inclusive total, tax total) for multiple values and a tax-exclusive calculation is required as described above, even if the tax calculation mode is switched from tax-inclusive to tax-exclusive calculation mode, the data (calculation results up to the middle of the calculation) in the tax-rate-specific total memory areas 22b-22f corresponding to each tax rate of 0-4 is not discarded (cleared). Therefore, even when performing a mixture of tax-inclusive and tax-exclusive calculations, the calculator 10 can switch tax calculation modes as necessary, allowing efficient tax calculations.

Next, a process according to an input operation to the tax calculation total key ([GST GT (GT)]) 11c in this embodiment will be described with reference to the flowchart shown in FIG.
The tax calculation total key 11c serves both as a grand total key ([GT] key) for displaying the grand total for normal calculation (basic calculation) and as a GST grand total key ([GST GT] key) for displaying the grand total for the tax calculation results.

When the CPU 21 detects the operation of the tax calculation total key 11c (step A21: Yes), it determines whether the tax total recall mode flag is on (step A22). When the CPU 21 determines that the tax total recall mode flag is on (step A22: Yes), it proceeds to step A29. In other words, regardless of whether the numerical value indicating the result of the executed tax calculation or normal calculation is being displayed on the display unit 12, that is, regardless of the display content of the display unit 12, when it determines that the tax total recall mode flag is on (step A22: Yes), it proceeds to step A29. When it determines that the tax total recall mode flag is on (step A22: No), it determines whether the operation on the tax calculation total key 11c is a normal press (an operation in which the key is held down for less than a predetermined time) or a long press operation (an operation in which the key is held down for a predetermined time or more).

If it is determined that the operation is a normal pressing operation (step A23: No), the CPU 21 determines whether the operation immediately before the pressing of the tax calculation total key 11c was a tax calculation. In other words, the CPU 21 determines whether the tax calculation total key 11c was operated immediately after the tax was calculated in response to the operation of the tax calculation key 11b, in other words, whether the tax calculation total key 11c was operated following the operation of the tax calculation key 11b.

If it is determined that the tax calculation total key 11c has been operated immediately after the tax calculation (step A26: Yes), the CPU 21 turns on the tax total recall mode stored in the tax total recall mode area 22k (step A28). In other words, the tax calculation total key 11c operated immediately after the tax calculation is used as a GST grand total key ([GST GT] key) for displaying the grand total of the tax calculation results.

In this case, the CPU 21 calculates the total tax-inclusive amount, the total tax-exclusive amount, and the total tax amount by adding up the tax-inclusive amount, the tax-exclusive amount, and the total tax amount calculated based on each tax rate 0 to 4 stored in the tax-rate-specific total tax memory areas 22b to 22f, and stores these amounts in the total tax memory area 22g. The CPU 21 also stores the calculated total tax-inclusive amount in the display memory area 22p and displays it on the display unit 12 (step A29).

When the tax-inclusive total amount is displayed (step A29), if the tax calculation total key 11c is operated (step A210: Yes), the CPU 21 reads out the tax-exclusive total amount from the tax total memory area 22g, stores it in the display memory area 22p, and displays it on the display unit 12 in place of the tax-inclusive total amount (step A211).

Furthermore, when the tax-excluded total amount is displayed (step A211), if the tax calculation total key 11c is operated (step A212, Yes), the CPU 21 reads out the tax-excluded total amount from the tax-excluded total memory area 22g, stores it in the display memory area 22p, and displays it on the display unit 12 in place of the tax-excluded total amount (step A213).

Furthermore, when the tax-inclusive total amount is displayed (step A213), if the tax calculation total key 11c is operated (step A214: Yes), the CPU 21 reads out the tax-inclusive total amount from the tax total memory area 22g, stores it in the display memory area 22p, and displays it on the display unit 12 in place of the tax total amount (step A29).

In other words, the calculator 10 in this embodiment calculates the total amount including tax in response to the operation of the tax calculation total key 11c, and can sequentially switch the display between the total amount including tax, the total amount excluding tax corresponding to the total amount including tax, and the total amount including tax corresponding to the total amount including tax, with each operation of the tax calculation total key 11c. This allows the total amount including tax, the total amount excluding tax, and the total amount including tax to be easily checked.

On the other hand, if the CPU 21 determines that the operation immediately before pressing the tax calculation total key 11c was not a tax calculation, i.e., that the tax calculation total key 11c was operated immediately after performing a normal calculation (step A26: No), it reads out the numerical value that is the result of the normal calculation stored in the total memory area 22h, stores it in the display memory area 22p, and displays it on the display unit 12 (step A27). In other words, the tax calculation total key 11c that is operated immediately after a normal calculation is used as a grand total key ([GT] key) for displaying the grand total calculated by the normal calculation.

Thus, in this embodiment of the calculator 10, a single tax calculation total key 11c is provided on the front of the case, which has a limited area, and serves as both a grand total key ([GT] key) and a GST grand total key ([GST GT] key). The function of the tax calculation total key 11c is switched depending on the previous state (immediately after tax calculation, immediately after normal calculation), so that the tax calculation total (total amount including tax, total amount excluding tax, total amount of tax) and the normal calculation total can be easily displayed.

When the CPU 21 detects operation of the tax calculation total key 11c (step A21: Yes), and determines that the operation on the tax calculation total key 11c is a long press operation (step A23: Yes), the CPU 21 executes processing to display the calculation result opposite to that when the tax calculation total key 11c described above is pressed.

That is, if the tax calculation total key 11c is pressed and held (step A23: Yes), and if the CPU 21 determines that the tax calculation total key 11c was operated immediately after the tax calculation (step A24: Yes), it reads out the numerical value that is the result of the normal calculation stored in the total memory area 22h, stores it in the display memory area 22p, and displays it on the display unit 12 (step A27).

If the tax calculation total key 11c is pressed and held (step A23: Yes), or if it is determined that the operation of the tax calculation total key 11c was not performed immediately after the tax calculation (step A24: No), the CPU 21 turns on the tax total recall mode stored in the tax total recall mode area 22k (step A28), as described above. The CPU 21 also calculates the total tax-inclusive amount, the total tax-exclusive amount, and the total tax amount calculated based on the tax rates 0 to 4 stored in the tax total memory areas 22b to 22f, and stores them in the tax total memory area 22g. The CPU 21 also stores the calculated total tax-inclusive amount in the display memory area 22p and displays it on the display unit 12 (step A29).

In this way, by pressing and holding the tax calculation total key 11c, the opposite process to that of the normal operation of pressing the tax calculation total key 11c can be executed. As a result, regardless of whether a tax calculation was performed immediately before operating the tax calculation total key 11c, the total amount of the tax calculation (total amount including tax, total amount excluding tax, total amount of tax) and the total amount of the normal calculation can be easily switched and displayed simply by changing the operation time (pressing time) of the tax calculation total key 11c.

Next, an example of specific numerical value input and tax calculation in this embodiment will be described. For ease of explanation, an example of tax calculation using two tax 1 calculation keys 11b1 [GST+1] (tax rate 1 (5%)) and tax 2 calculation key 11b2 [GST+2] (tax rate 2 (10%)) will be described. Detailed explanations of tax calculation using tax 0 calculation key 11b0, tax 3 calculation key 11b3, and tax 4 calculation key 11b4 will be omitted, as it is performed in the same way as when tax 1 calculation key 11b1 and tax 2 calculation key 11b2 are operated.

Figures 8 (A) and (B) show specific key operations used in the following explanation, numerical values displayed on the display unit 12, the tax-inclusive total amount, tax-exclusive total amount, and tax total amount stored in the tax rate 1 total memory area 22c and the tax rate 2 total memory area 22d, respectively, and the total amount of normal calculations stored in the total memory area 22h. The key operations shown in Figures 8 (A) and (B) show an example of performing a mixture of tax calculation and normal calculation. Figure 8 (A) shows key operations when the operation immediately before the tax calculation total key 11c is operated is tax calculation, and Figure 8 (B) shows key operations when the operation immediately before the tax calculation total key 11c is operated is not tax calculation. Figure 9 shows the key operations shown in Figure 8 (A) and an example of display on the display unit 12.

When the [AC] key 11a is operated, the CPU 21 clears the tax total memory areas 22b to 22f by tax rate (Figure 9 (A)). The CPU 21 also refers to the tax calculation mode area 22m, and if it determines that the current tax calculation mode is the tax-inclusive calculation mode, it displays [GST+] as the tax calculation mode symbol 12b in the status display area of the display unit 12. If it determines that the current tax calculation mode is the tax-exclusive calculation mode, it displays [TAX-] as the tax calculation mode symbol 12b in the status display area of the display unit 12. As mentioned above, the tax calculation mode does not change even if the [AC] key 11a is operated, so Figure 9 (A) is an example of a display when the tax calculation mode immediately before the operation of the [AC] key 11a was the tax-inclusive calculation mode.

After that, when the value "200" is input for tax calculation, the CPU 21 stores the input value in the display memory area 22p and displays it on the display unit 12. Next, when the tax 1 calculation key 11b1 is operated, the CPU 21 displays the tax-inclusive amount "210" calculated based on the tax rate 1 and "GST+1" as the tax calculation key symbol 12c on the display unit 12 (FIG. 9 (B1)). The CPU 21 also stores the result of the tax calculation using the tax rate 1 by the tax 1 calculation key 11b1 in the tax rate 1 total memory area 22c. In this case, as shown in FIG. 8 (A), the tax-inclusive total amount "210" for tax rate 1, the tax-exclusive total amount "200" for tax rate 1, and the tax-exclusive total amount "10" for tax rate 1 are stored in the tax rate 1 total memory area 22c. At the same time, the tax-exclusive amount "200" is stored in the buffer memory area 22n (not shown).

Next, when the "100", [x], "7", and [=] keys are operated for normal calculation, the CPU 21 executes the normal calculation of "100 x 7 = 700", stores the result of the calculation "700" in the display memory area 22p, and displays it on the display unit 12 (FIG. 9 (B2)). The CPU 21 also stores the result of the normal calculation in the total memory area 22h. Furthermore, the CPU 21 displays "GT" as the grand total display symbol 12e in the status display area of the display unit 12.

Next, when the number "300" is input for tax calculation, the CPU 21 stores the input number in the display memory area 22p and displays it on the display unit 12. Next, when the tax 1 calculation key 11b1 is operated, the CPU 21 stores the tax-included amount "315" calculated based on the number "300" displayed on the display unit 12 and tax rate 1 in the display memory area 22p and displays it on the display unit 12. At the same time, the CPU 21 displays the tax calculation key symbol "GST+1" on the display unit 12 (FIG. 9 (B3)). The CPU 21 also stores the result of the tax calculation using tax rate 1 by the tax 1 calculation key 11b1 in the tax rate 1 total memory area 22c. In this case, the tax calculation results for the value "300", that is, the tax-inclusive amount for tax rate 1 of "315", the tax-exclusive amount for tax rate 1 of "300", and the tax amount for tax rate 1 of "15", are added to the previously stored total amount including tax for tax rate 1 of "210", the total amount excluding tax for tax rate 1 of "200", and the total amount of tax for tax rate 1 of "10", as shown in Fig. 8 (A). As a result, the total amount including tax for tax rate 1 of "525", the total amount excluding tax for tax rate 1 of "500", and the total amount of tax for tax rate 1 of "25" are stored in the tax rate 1 total memory area 22c. At the same time, the tax-exclusive amount "300" is stored in the buffer memory area 22n (not shown).

Similarly, when the number "1000" is input and the tax 2 calculation key 11b2 is operated, and then the number "2000" is input and the tax 2 calculation key 11b2 is operated, the CPU 21 stores the tax-inclusive amount ("1100", "2200") of the tax rate 2 calculated based on the tax-exclusive amount and the tax rate 2, with each operation of the tax 2 calculation key 11b2 as the tax-exclusive amount, in the display memory area 22p in sequence, and displays it in sequence on the display unit 12. At the same time, the CPU 21 displays the tax calculation key symbol "GST+2" on the display unit 12 (FIG. 9 (B4) (B5)). The CPU 21 also stores the result of the tax calculation using the tax rate 2 by the tax 2 calculation key 11b2 in the tax rate 2 total memory area 22d, as shown in FIG. 8 (A). At the same time, first, the tax-excluded amount "1000" is stored in the buffer memory area 22n, and then the tax-excluded amount "2000" is stored in the buffer memory area 22n (not shown).

In this way, the calculator 10 in this embodiment can arbitrarily specify the tax rate used to calculate the tax on the input value by operating the tax 1 calculation key 11b1 or the tax 2 calculation key 11b2. Therefore, for example, when calculating the tax-inclusive total amount of multiple products with different applicable tax rates, even if multiple products with different applicable tax rates are mixed, the tax-inclusive amount can be input by specifying the tax rate for each product. In addition, the results of the tax calculation using the tax 1 calculation key 11b1 or the tax 2 calculation key 11b2 (tax-inclusive amount, tax-exclusive amount, tax amount) can be stored individually in the tax rate 1 total memory area 22c and the tax rate 2 total memory area 22d. Therefore, as described below, in the tax total recall mode, the results of the tax calculation can be displayed by tax rate in response to the operation of the tax 1 calculation key 11b1 or the tax 2 calculation key 11b2.

Figures 9 (C1) to (C3) and Figure 9 (F1) show examples of the display when the tax calculation total key [GST GT (GT)] 11c is operated (see Figure 4).

When the tax calculation total key 11c is pressed normally after the tax calculation for the multiple values shown in Fig. 9 (B1) to (B5), the CPU 21 turns on the tax total recall mode since it is immediately after the tax calculation. The CPU 21 also calculates the total tax-inclusive total amount "3825" indicating the sum of the tax-inclusive total amount (525 + 3300) to which the tax rate 1 and the tax rate 2 are respectively applied based on the tax-inclusive amount, the tax-exclusive total amount, and the tax total amount for the tax rate 1 and the tax rate 2 stored in the tax rate 1 total memory area 22c and the tax rate 2 total memory area 22d to 22f, and stores this in the tax total memory area 22g and displays it on the display unit 12 (third line from the bottom in Fig. 8 (A), Fig. 9 (C1)). Furthermore, the CPU 21 displays "RCL" as the tax total recall mode symbol 12d in the status display area of the display unit 12 (Fig. 9 (C1)). Here, when the tax calculation total key 11c is operated, the CPU 21 displays the tax-excluded total amount "3500" which indicates the sum of the tax-excluded total amounts to which tax rate 1 and tax rate 2 are applied, as shown in Fig. 9 (C2). When the tax calculation total key 11c is further operated, the CPU 21 displays the tax-excluded total amount "325" which indicates the sum of the tax-excluded total amounts to which tax rate 1 and tax rate 2 are applied, as shown in Fig. 9 (C3). When the tax calculation total key 11c is further operated, the CPU 21 returns to the display shown in Fig. 9 (C1), reads out the tax-excluded total amount "3825" from the tax total memory area 22g, and displays it on the display unit 12.

On the other hand, after calculating the tax for the multiple values shown in Figures 9 (B1) to (B5), if the tax calculation total key 11c is pressed and held, the CPU 21 reads out and displays the total amount of the normal calculations "700" stored in the total memory area 22h (first line from the bottom in Figure 8 (A), Figure 9 (F1)).

Next, the key operations shown in FIG. 8(B) will be described. Note that the tax calculation shown in FIG. 8(B) is executed in the same manner as in FIG. 8(A) described above, and detailed explanation will be omitted. In FIG. 8(B), after tax calculation for multiple numerical values (200[GST+1], 300[GST+1], 1000[GST+1], 2000[GST+1]), normal calculation (100[x], 7[=]) is executed, and immediately after that, the tax calculation total key 11c is operated.

In this case, in response to the operation of the tax calculation total key 11c, the CPU 21 displays the total amount of the regular calculations stored in the total memory area 22h, which is "700" (third line from the bottom in Figure 8 (B) and Figure 9 (F1)).

On the other hand, when the tax calculation total key 11c is pressed and held after the tax calculation for the multiple values shown in the first to sixth lines of FIG. 8(B) is performed, the CPU 21 turns on the tax total recall mode. The CPU 21 also calculates the total tax-inclusive amount "3825" which indicates the sum of the tax-inclusive amount (525 + 3300) to which tax rate 1 and tax rate 2 are applied based on the tax-inclusive amount, tax-exclusive amount, and tax total amount for tax rate 1 and tax rate 2 stored in the tax rate 1 total memory area 22c and the tax rate 2 total memory area 22d, and stores this in the tax total memory area 22g and displays it on the display unit 12 (first line from the bottom in FIG. 8(B), FIG. 9(C1)). Furthermore, the CPU 21 displays "RCL" as the tax total recall mode symbol 12d in the status display area of the display unit 12 (FIG. 9(C1)).

In this way, the total amount based on the normal calculation can be displayed by operating (short press) the tax calculation total key 11c immediately after performing the normal calculation, or by pressing and holding the tax calculation total key 11c immediately after performing the tax calculation. Also, as described above, the total amount based on the tax calculation can be displayed by operating (short press) the tax calculation total key 11c immediately after performing the tax calculation, or by pressing and holding the tax calculation total key 11c immediately after performing the normal calculation, so that one tax calculation total key 11c can be used differently depending on the immediately preceding operating state.

Next, we will explain what happens when the tax 1 calculation key 11b1 or tax 2 calculation key 11b2 is operated after the tax total recall mode is turned on.

Figures 9 (D1) to (D3) show examples of the display when the tax 1 calculation key 11b1 is operated. When the tax 1 calculation key 11b1 is operated in the state in which the display shown in Figures 9 (C1) to (C3) is shown, the CPU 21 displays the first tax-inclusive total amount "525" calculated based on tax rate 1, as shown in Figure 9 (D1). Here, when the tax 1 calculation key 11b1 is operated, the CPU 21 displays the first tax-excluded total amount "500" as shown in Figure 9 (D2). Furthermore, when the tax 1 calculation key 11b1 is operated, the CPU 21 displays the first tax-inclusive total amount "25" as shown in Figure 9 (D3). Furthermore, when the tax 1 calculation key 11b1 is operated, the CPU 21 returns to the display shown in Figure 9 (D1) and displays the first tax-inclusive total amount "525".

When the tax 2 calculation key 11b2 is operated in the display state shown in Figures 9 (D1) to (D3), the CPU 21 switches to the display of the second total amount including tax shown in Figure 9 (E1) described below. Also, when the tax calculation total key 11c is operated in the display state shown in Figures 9 (D1) to (D3), the CPU 21 transitions to the display state of the total amount including tax shown in Figure 9 (C1) described above.

9 (E1) to (E3) show examples of the display when the tax 2 calculation key 11b2 is operated. When the tax 2 calculation key 11b2 is operated in the state shown in FIG. 9 (C1) to (C3), the CPU 21 displays the second tax-inclusive total amount "3300" calculated based on the tax rate 2, as shown in FIG. 9 (E1). When the tax 2 calculation key 11b2 is operated, the CPU 21 displays the second tax-excluded total amount "3000" as shown in FIG. 9 (E2). When the tax 2 calculation key 11b2 is further operated, the CPU 21 displays the second tax-inclusive total amount "300" as shown in FIG. 8 (E3). When the tax 2 calculation key 11b2 is further operated, the CPU 21 returns to the display shown in FIG. 9 (E1) and displays the second tax-inclusive total amount "3300".

When the tax 1 calculation key 11b1 is operated in the display state shown in Figures 9 (E1) to (E3), the CPU 21 switches to the display of the first tax-inclusive total amount shown in Figure 9 (D1). Also, when the tax calculation total key 11c is operated in the display state shown in Figures 9 (E1) to (E3), the CPU 21 transitions to the display state of the tax-inclusive total amount shown in Figure 9 (C1) described above.

Thus, while the tax total recall mode is on, the calculator 10 in this embodiment can switch between displaying the tax-inclusive total amount, tax-exclusive total amount, and tax total amount for tax rate 1 and tax rate 2 by simply operating the tax 1 calculation key 11b1 and tax 2 calculation key 11b2. This allows the user to easily check the tax-inclusive total amount, tax-exclusive total amount, and tax total amount for each tax rate.

In addition, while the tax total recall mode is on, the calculator 10 in this embodiment can switch between displaying the grand total (FIG. 9 (C1) to (C3)), displaying the total for tax rate 1 corresponding to the tax 1 calculation key 11b1 (FIG. 9 (D1) to (D3)), and displaying the total for tax rate 2 corresponding to the tax 2 calculation key 11b2 (FIG. 9 (E1) to (E3)), by operating the tax calculation total key 11c, tax 1 calculation key 11b1, and tax 2 calculation key 11b2.

Next, we will explain the case where both tax-inclusive and tax-exclusive calculations are performed. Figure 10 shows the specific key operations used in the following explanation, the numerical values displayed on the display unit 12, and the total amount including tax, the total amount excluding tax, and the total tax amount stored in the tax rate 1 total memory area 22c and the tax rate 2 total memory area 22d, respectively.

The key operations shown in Figures 8(A) and 8(B) above explain the case where only calculations including tax are performed, while the key operations shown in Figure 10 show an example where the calculation mode is switched to the calculation mode excluding tax in the middle of a calculation including tax.

When the [AC] key 11a is operated, the CPU 21 clears the tax-by-tax-rate total memory areas 22b to 22f. Here, the calculation mode is the tax-inclusive calculation mode, and the display unit 12 displays [GST+], which indicates the tax-inclusive calculation mode, as the tax calculation mode symbol 12b.

After that, when the number "200" is input as the tax-excluded amount for tax calculation (tax-inclusive calculation) and the tax 1 calculation key 11b1 ([GST+1(TAX-1)]) is operated, the CPU 21 stores the input number in the buffer memory area 22n and displays the tax-inclusive amount "210" calculated by tax-inclusive calculation based on the tax-excluded amount and tax rate 1, and the symbol "GST+1" indicating that the tax-inclusive amount calculated based on tax rate 1 is displayed. The CPU 21 also stores the result of the tax calculation using tax rate 1 by the tax 1 calculation key 11b1 in the tax rate 1 total memory area 22c. In this case, as shown in FIG. 9, the tax-inclusive total amount "210" for tax rate 1, the tax-excluded total amount "200" for tax rate 1, and the tax total amount "10" for tax rate 1 are stored in the tax rate 1 total memory area 22c.

Similarly, when the value "300" is entered as the tax-exclusive amount for tax calculation and the tax 2 calculation key 11b2 is operated, the CPU 21 stores the entered value in the buffer memory area 22n, and displays the tax-inclusive amount "330" calculated by tax-inclusive calculation based on the tax-exclusive amount and tax rate 2, and the symbol "GST+2" indicating that the tax-inclusive amount calculated based on tax rate 2 is displayed. The CPU 21 also stores the result of the tax calculation using tax rate 2 by the tax 2 calculation key 11b2 in the tax rate 2 total memory area 22d. In this case, as shown in FIG. 10, the tax-inclusive total amount "330" for tax rate 2, the tax-exclusive total amount "300" for tax rate 2, and the tax total amount "30" for tax rate 2 are stored in the tax rate 2 total memory area 22d.

Next, when the tax 2 calculation key 11b2 is operated while the tax-inclusive total amount "330" for tax rate 2 is displayed, the CPU 21 reads out the tax-excluded amount "300" stored in the buffer memory area 22n and displays it on the display unit 12.

Here, it is assumed that the tax calculation mode switching key 11d ([GST+/TAX-]) is operated to change the calculation mode to the tax-exclusive calculation mode. When the CPU 21 detects the operation of the tax calculation mode switching key 11d, it switches the calculation mode to the tax-exclusive calculation mode. The CPU 21 also displays [TAX-], which indicates the tax-inclusive calculation mode, as the tax calculation mode symbol 12b on the display unit 12.

After that, when the value "660" is entered as the tax-inclusive amount for tax calculation (tax-exclusive calculation) and the tax 2 calculation key 11b2 ([GST+2(TAX-2)]) is operated, the CPU 21 stores the entered value in the buffer memory area 22n and displays the tax-exclusive amount "600" calculated by tax-exclusive calculation based on the tax-inclusive amount and tax rate 2, as well as the symbol "TAX-2" indicating that the tax-exclusive amount calculated based on tax rate 2 is being displayed. In the tax-exclusive calculation, as shown in FIG. 10, the result of the tax-exclusive calculation is not reflected in the tax rate 2 total memory area 22d.

Here, it is assumed that the tax calculation mode switching key 11d ([GST+/TAX-]) is operated to change the calculation mode to the tax-inclusive calculation mode. When the CPU 21 detects the operation of the tax calculation mode switching key 11d, it switches the calculation mode to the tax-inclusive calculation mode.

After that, when the tax 1 calculation key 11b1 ([GST+1)]) is operated while the tax-excluded calculation results in a value of "600" for tax calculation (tax-inclusive calculation), the CPU 21 displays the tax-inclusive amount "630" calculated by tax-inclusive calculation based on the displayed value and tax rate 1, and the symbol "GST+1" indicating that the tax-inclusive amount calculated based on tax rate 1 is displayed. The CPU 21 also adds the result of the tax calculation using tax rate 1 by the tax 1 calculation key 11b1 (tax-excluded amount, tax-inclusive amount, tax amount) to the value previously stored in the tax rate 1 total memory area 22c. As a result, the tax rate 1 total memory area 22c stores the tax rate 1 total amount including tax "840", the tax-excluded total amount "800" for tax rate 1, and the tax total amount "30" for tax rate 1.

In this way, when performing a tax-inclusive calculation using tax rate 1 for the number "660" indicating the tax-inclusive amount using tax rate 2, it is possible to switch to tax-exclusive calculation mode in the middle of the tax-inclusive calculation and perform a tax-exclusive calculation to calculate the tax-exclusive amount of the number "660". The number (number entered) displayed on the display unit 12 as the result of the tax-exclusive calculation can be used as is for the tax calculation. Furthermore, the tax-exclusive calculation does not affect the numbers stored in the tax rate 1 total memory area 22c and the tax rate 2 total memory area 22d. Therefore, by switching the tax calculation mode back to the tax-inclusive calculation mode and selecting a different tax rate 1 for the displayed number to perform a tax-inclusive calculation, the result of the tax-inclusive calculation using tax rate 1 can be reflected in the tax rate 1 total memory area 22c.

Therefore, in a market that uses multiple consumption tax rates, such as India, if a tax calculation is required based on the product price listed inclusive of tax, using a different tax rate, you can switch to tax-exclusive calculation mode, perform a tax-exclusive calculation to obtain the price exclusive of tax, and then perform a tax-inclusive calculation using the other tax rate.

Next, we will explain the case where tax calculation and normal calculation are performed together. Figure 11 shows the specific key operations used in the following explanation, the values displayed on the display unit 12, and the tax-inclusive total amount, tax-exclusive total amount, and tax total amount stored in the tax rate 1 total memory area 22c and the tax rate 2 total memory area 22d, respectively. Here, we will explain an example of performing arithmetic operations using the values (numbers) obtained by tax calculation. Note that the downward arrows in columns 3 to 8 in Figure 10 indicate that the values in the sixth row to the second row from the bottom of each column are the same as the value in the fifth row of each column (the value does not change).

When the [AC] key 11a is operated, the CPU 21 clears the tax-by-tax-rate total memory areas 22b to 22f. Here, the calculation mode is the tax-inclusive calculation mode, and the display unit 12 displays [GST+], which indicates the tax-inclusive calculation mode, as the tax calculation mode symbol 12b.

Next, when the number "200" is input as the tax-exclusive amount and the tax 1 calculation key 11b1 is operated, the CPU 21 stores the input number in the buffer memory area 22n, and displays the tax-inclusive amount "210" calculated by tax-inclusive calculation based on the tax-exclusive amount and tax rate 1, and the symbol "GST+1" indicating that the tax-inclusive amount calculated based on tax rate 1 is displayed. The CPU 21 also stores the result of the tax calculation using tax rate 1 by the tax 1 calculation key 11b1 in the tax rate 1 total memory area 22c. In this case, as shown in FIG. 11, the tax-inclusive total amount "210" for tax rate 1, the tax-exclusive total amount "200" for tax rate 1, and the tax total amount "10" for tax rate 1 are stored in the tax rate 1 total memory area 22c.

Similarly, when the number "200" is entered as the tax-exclusive amount and the tax 1 calculation key 11b1 is operated, the CPU 21 stores the entered number in the buffer memory area 22n and displays the tax-inclusive amount "315" calculated by a tax-inclusive calculation based on the tax-exclusive amount and tax rate 1. The CPU 21 also adds the result of the tax calculation using tax rate 1 to the number stored in the tax rate 1 total memory area 22c. As a result, as shown in FIG. 11, the tax-inclusive total amount for tax rate 1 "525", the tax-exclusive total amount for tax rate 1 "500", and the tax total amount for tax rate 1 "25" are stored in the tax rate 1 total memory area 22c.

Next, when the number "1000" is input as the tax-exclusive amount and the tax 2 calculation key 11b2 is operated, the CPU 21 stores the input number in the buffer memory area 22n, and displays the tax-inclusive amount "1100" calculated by tax-inclusive calculation based on the tax-exclusive amount and tax rate 2, and the symbol "GST+2" indicating that the tax-inclusive amount calculated based on tax rate 2 is displayed. The CPU 21 also stores the result of the tax calculation using tax rate 2 by the tax 2 calculation key 11b2 in the tax rate 2 total memory area 22d. In this case, as shown in FIG. 11, the tax-inclusive total amount for tax rate 2 "1100", the tax-exclusive total amount for tax rate 2 "1000", and the tax total amount for tax rate 2 "100" are stored in the tax rate 2 total memory area 22d.

Similarly, when the number "2000" is entered as the tax-exclusive amount and the tax 2 calculation key 11b2 is operated, the CPU 21 stores the entered number in the buffer memory area 22n and displays the tax-inclusive amount "2200" calculated by tax-inclusive calculation based on the tax-exclusive amount and tax rate 2. The CPU 21 also adds the result of the tax calculation using tax rate 2 to the number stored in the tax rate 2 total memory area 22d. As a result, as shown in FIG. 11, the tax-inclusive total amount for tax rate 2 "3300", the tax-exclusive total amount for tax rate 2 "3000", and the tax total amount for tax rate 2 "300" are stored in the tax rate 2 total memory area 22d.

Here, assume that the tax calculation total key 11c is pressed in the normal way to display the tax calculation total. The CPU 21 detects that the tax calculation total key 11c has been operated and determines whether the tax total recall mode is on. If the CPU 21 detects that the tax total recall mode is not on and that the operation is performed immediately after the tax calculation, it turns on the tax total recall mode and displays "RCL" on the display unit 12, indicating that the tax total recall mode is on. The "RCL" on the left side of the table in FIG. 11 indicates that the corresponding row is in recall mode while it is being displayed. The downward arrow indicates that the recall mode continues from the sixth row down to the second row, i.e., until just before the [AC] key is pressed.

When the tax total recall mode transitions to the on state, the CPU 21 stores the tax-inclusive total amount "3825", which is the sum of the tax-inclusive total amounts calculated using tax rate 1 and tax rate 2, in the tax total memory area 22g and displays it on the display unit 12. Here, when the tax calculation total key 11c is operated repeatedly, the CPU 21 sequentially calculates the tax-excluded total amount "3500" and the tax total amount "325" in response to the key operation, stores them in the tax total memory area 22g, and reads them out from the display unit 12 for display.

When the tax total amount "325" is displayed and the keys [÷], [2], and [=] are pressed to perform arithmetic, the CPU 21 performs arithmetic on the number "325" displayed on the display unit 12, "325÷2=162.5", and displays the resultant number "162.5" on the display unit 12. The number "162.5" is stored in the total memory area 22h. It is possible to perform arithmetic not only by displaying the tax total amount and performing arithmetic, but also by displaying the tax-inclusive total amount or the tax-exclusive total amount and performing arithmetic.

In this way, even if an arithmetic key or a numeric key is operated for arithmetic calculation during tax calculation, the on state of the tax total recall mode is maintained. In addition, the numerical values stored in the tax rate 1 total memory area 22c, the tax rate 2 total memory area 22d, and the tax total memory area 22g that were stored by the tax calculation are also maintained.

Here, it is assumed that the tax calculation total key 11c is pressed in the usual way to display the tax calculation total. When the CPU 21 detects that the tax calculation total key 11c has been operated, it determines whether the tax total recall mode is on. At this time, the tax total recall mode is already on. Therefore, the CPU 21 displays the tax-inclusive total amount stored in the tax total memory area 22g on the display unit 12 in response to the operation of the tax calculation total key 11c. That is, when the tax total recall mode is set to on and an instruction to read the tax-inclusive total amount is input by operating the tax calculation total key 11c, the CPU 21 reads out the tax-inclusive total amount "3825" stored in the display memory area 22p while displaying the number "162.5" resulting from the execution of the four arithmetic operations, and displays it on the display unit 12.

Next, assume that the tax 1 calculation key 11b1 is operated to display the tax-inclusive total amount calculated using tax rate 1. When the tax 1 calculation key 11b1 is operated, the tax total recall mode is on, so the CPU 21 reads out the first tax-inclusive total amount "525" stored in the tax rate 1 total memory area 22c and displays it on the display unit 12, instead of displaying the tax-inclusive total amount "3825".

Here, when the tax calculation total key 11c is operated again, the CPU 21, in the same manner as described above, causes the display unit 12 to display the tax-inclusive total amount "3825" stored in the tax total memory area 22g in response to the operation of the tax calculation total key 11c. In other words, when the tax total recall mode is set to the ON state, not only when the numerical value calculated as the result of normal calculation by arithmetic operations is being displayed, but also when the numerical value calculated as the result of tax calculation is being displayed on the display unit 12, the tax-inclusive total amount can be displayed in response to the operation of the tax calculation total key 11c. In other words, after the tax total recall mode is set to the ON state, the tax-inclusive total amount can be displayed regardless of the display content when the tax calculation total key 11c is operated. Furthermore, it is assumed that the tax 2 calculation key 11b2 is operated to display the tax-inclusive total amount of tax calculation using tax rate 2. When the tax 2 calculation key 11b2 is operated, the CPU 21 reads out the second tax-inclusive total amount "3300" stored in the tax rate 2 total memory area 22d and displays it on the display unit 12, instead of displaying the tax-inclusive total amount "3825" in response to the operation of the tax 2 calculation key 11b2.

In other words, as shown in FIG. 11, when a numerical value related to the result of tax calculation based on tax rate 1 is stored in tax rate 1 total memory area 22c, and a numerical value related to the result of tax calculation based on tax rate 2 is stored in tax rate 2 total memory area 22d, in a state where the tax total recall mode is set to the on state, the numerical value stored in tax rate 1 total memory area 22c (total amount including tax) can be read and displayed in response to operation of tax 1 calculation key 11b1, and similarly, the numerical value stored in tax rate 2 total memory area 22d (total amount including tax) can be read and displayed in response to operation of tax 2 calculation key 11b2.

Although not shown, if numerical values related to the results of tax calculations based on tax rates 0, 3, and 4 are stored in the tax rate 0 total memory area 22b, the tax rate 3 total memory area 22e, and the tax rate 4 total memory area 22f, respectively, the corresponding numerical values (total amount including tax) can be read out and displayed in response to the operation of the tax 0 calculation key 11b0, the tax 3 calculation key 11b3, or the tax 4 calculation key 11b4.

In the above explanation, when the tax total recall mode is on, at least the tax-inclusive total is displayed in response to the operation of the tax n calculation keys 11b0 to 11b4, but it is also possible to display both the tax-exclusive total and/or the tax total.

Next, when the tax 2 calculation key 11b2 is operated repeatedly while the second tax-inclusive total amount "3300" is displayed, the CPU 21 reads out the tax-excluded total amount "3000" and the tax total amount "300" from the tax rate 2 total memory area 22d in response to the key operation, and displays them sequentially on the display unit 12.

When the total tax amount "300" is displayed and the keys [÷], [2], and [=] are entered to perform arithmetic, the CPU 21 performs arithmetic on the number "300" displayed on the display unit 12, "300÷2=150", and displays the resultant number "150" on the display unit 12. The number "150" is added to the number stored in the total memory area 22h. Note that in addition to displaying the total tax amount and performing arithmetic, it is also possible to display the total amount including tax or the total amount excluding tax and perform arithmetic.

When the CPU 21 detects that the [AC] key has been operated, it turns off the tax total recall mode and clears all memory, including the tax total memory areas 22b to 22f by tax rate and the tax total memory area 22g.

In this way, the tax total recall mode remains on until the [AC] key is operated. When the tax total recall mode is on, the values stored in the tax total memory areas 22b to 22f by tax rate can be displayed on the display unit 12 by operating the tax calculation key 11b, and can be used for normal calculation.

In this way, in the calculator 10 of this embodiment, when the tax total recall mode is on, the tax total recall mode is maintained on even when a normal calculation is performed, so that tax calculation and normal calculation can be performed separately and the respective calculation results can be stored. Therefore, tax calculation and normal calculation can be easily performed in a mixed manner. In addition, the total amount (total amount including tax, total amount excluding tax, total amount of tax) by the tax calculation stored in the tax total memory area 22g, or the calculation results (total amount including tax, total amount excluding tax, total amount of tax) by each tax rate stored in the tax rate 1 total memory area 22c can be displayed on the display unit 12 in response to key operations and used as the subject of normal calculation. Therefore, normal calculation using the result of tax calculation (number of entries) as the subject can be easily performed.

Figure 12 is an example of a receipt format used in retail stores in India, with an excerpt of the column for entering the total amount. The receipt allows the entry of figures for five different tax rates, with columns from top to bottom for the total amount excluding tax by tax rate, State GST (SGST) by tax rate, Central GST (CGST) by tax rate, Inter-State GST (IGST) by tax rate, total amount including tax by tax rate, and grand total including tax. Figures are entered into each column according to the tax calculation actually performed at the store.

The entry of values into the slip will be explained with reference to the input operation example shown in FIG. 11. When the tax calculation total key 11c is operated immediately after the tax calculation, the tax total recall mode is turned on, and the tax-inclusive total amount "3825" is displayed on the display unit 12 (line 6 of FIG. 11). The person who enters the value looks at this value and transfers it to the "GTAND TOTAL" column on the slip (line 6 of FIG. 12). Next, when the tax 2 calculation key 11b2 is operated, the second tax-inclusive total amount "3300" is displayed on the display unit 12 (line 14 of FIG. 11), and the person who enters the value transfers it to the tax rate 2 tax-inclusive total amount column on the slip (column 3, line 5 of FIG. 12). When the tax 2 calculation key 11b2 is operated again, the second tax-excluded total amount "3000" is displayed on the display unit 12 (line 15 of FIG. 11), and the person who writes the entry transfers the value to the tax-excluded total amount column of tax rate 2 in the slip (line 1 of column 3 of FIG. 12). Next, when the tax 2 calculation key 11b2 is operated again, the tax total amount "300" of tax rate 2 is displayed on the display unit 12 (line 16 of FIG. 11), and then, when the displayed value is used to calculate half of the tax total amount of tax rate 2, "150" is displayed on the display unit 12 as the result of the execution of the normal calculation (line 18 of FIG. 11). The person who writes the entry transfers the values to the SGST and CGST columns of tax rate 2 in the slip (line 2 and 3 of column 3 of FIG. 12). In this example, it is assumed that there is no particular value to be transferred to the IGST column. Although not illustrated in FIG. 10, by operating the Tax 1 calculation key 11b1 while the tax total recall mode is on, the tax calculation result or the result of a normal calculation targeting the tax calculation result can be displayed for tax rate 1, just as with tax rate 2, and the values can be transferred to each column of the invoice, as shown in the second column of FIG. 12.

In this way, according to the calculator of this embodiment, after the tax calculation is completed, the tax total recall mode is turned on, and the calculated total tax amounts are used to calculate the SGST, CGST, or IGST by normal calculation. Moreover, once the tax total recall mode is turned on, the on state is maintained unless a specific operation (operation of the [AC] key) is performed, and the numerical values stored in the tax total memory areas 22b to 22f and the tax total memory area 22g are retained. Therefore, after the tax calculation is completed, the total tax amount (tax-inclusive amount/tax-exclusive amount/tax amount) or the total tax amounts for multiple tax rates (tax-inclusive amount/tax-exclusive amount/tax amount) can be called up and displayed on the display unit 12 at any time by operating the tax calculation total key 11c or the tax calculation key 11b, and the SGST, CGST, or IGST for the total tax amount or the total tax amounts for multiple tax rates can be calculated at any time by performing normal calculation using the displayed numerical values. Therefore, the calculator of this embodiment makes it easy to transfer to a voucher, especially when you perform normal calculations based on each value before transferring the total tax amount or the total tax amount by tax rate to a voucher, rather than transferring the total tax amount to a voucher as is.

The methods described in the embodiments, i.e., the processes shown in the flowcharts of Figures 3 to 7, can be stored and distributed as programs that can be executed by a computer on a recording medium such as a memory card (ROM card, RAM card, etc.), a magnetic disk (flexible disk, hard disk, etc.), an optical disk (CD-ROM, DVD, etc.), or a semiconductor memory. The computer can then read the program recorded on the external recording medium, and its operation can be controlled by this program, thereby realizing processes similar to the functions described in the embodiments.

In addition, the program data for implementing each method can be transmitted over a network (Internet) in the form of program code, and the program data can be imported from a computer (server device, etc.) connected to this network (Internet) to realize functions similar to those of the above-mentioned embodiments.

The present invention is not limited to the embodiments, and can be modified in various ways in the implementation stage without departing from the gist of the invention. Furthermore, the embodiments include inventions at various stages, and various inventions can be extracted by appropriate combinations of the multiple constituent elements disclosed. For example, even if some constituent elements are deleted from all the constituent elements shown in the embodiments, or some constituent elements are combined, if the problem described in the "Problem to be Solved by the Invention" column can be solved and the effect described in the "Effect of the Invention" column can be obtained, the configuration in which the constituent elements are deleted or combined can be extracted as the invention.

The inventions described in the original claims of this application are set forth below.

[1] In response to an input of an instruction to execute a first calculation, execute a first calculation using numerical values, store a first numerical value relating to the result of the executed first calculation in a first memory, and display the first numerical value on a display unit;
execute a second calculation using numerical values in response to an input of an instruction to execute a second calculation different from the first calculation, store a second numerical value related to the result of the executed second calculation in a second memory, and display the second numerical value on the display unit;
when a first read instruction is input while a numerical value indicating a result of the executed first calculation is being displayed on the display unit, the first numerical value stored in the first memory is displayed on the display unit;
A calculator having a control unit that, when the first read instruction is input while a numerical value indicating the result of the executed second calculation is being displayed on the display unit, causes the second numerical value stored in the second memory to be displayed on the display unit.

[2] The control unit is
2. The calculator according to claim 1, wherein a readout mode is set to display the first numerical value related to the result of the first calculation executed in response to an input of a readout mode setting instruction.

[3] The computer according to [2], wherein the first read instruction also serves as an instruction to set the read mode.

[4] The control unit is
In a state where the read mode is set,
A calculator according to [2] or [3], which, in response to an input of an instruction to execute the second calculation, executes a second calculation using numerical values being displayed on the display unit without canceling the set readout mode, and displays numerical values indicating a result of the executed second calculation on the display unit.

[5] The control unit is
In a state where the read mode is set,
In response to an input of a second read instruction, the first numerical value stored in the first memory is read and displayed on the display unit;
A calculator as described in any one of [2] to [4], wherein, in response to an input of an instruction to execute the second calculation, the second calculation is executed using the first numerical value being displayed on the display unit without canceling the set readout mode, and a numerical value indicating a result of the executed second calculation is displayed on the display unit.

[6] The computer described in [5], in which the instruction to execute the first calculation also serves as the instruction to read the second calculation.

[7] The control unit is
In a state where the read mode is set,
The computer according to any one of [2] to [6], wherein the set read mode is cancelled in response to input of a predetermined instruction.

[8] The control unit is
In a state where the read mode is set,
The computer according to any one of [2] to [7], further comprising: a first memory that clears the contents of the first memory in response to input of a predetermined instruction.

[9] The control unit is
In a state where the read mode is set,
A calculator as described in any one of [2] to [8], wherein when the first read instruction is input, the first numerical value stored in the first memory is displayed on the display unit regardless of the display content of the display unit.

[10] The control unit is
When the read mode is not set,
when the first read instruction is input while a numerical value indicating the result of the executed first calculation is being displayed on the display unit, the first numerical value stored in the first memory is displayed on the display unit;
A calculator as described in any one of [2] to [9], wherein when the first read instruction is input while a numerical value indicating the result of the executed second calculation is being displayed on the display unit, the second numerical value stored in the second memory is displayed on the display unit.

[11] The control unit is
When an instruction to execute the first calculation related to a first tax rate is input, a tax calculation based on the first tax rate is executed, and a third value related to the result of the tax calculation based on the first tax rate is stored in the first memory;
When an instruction to execute the first calculation related to a second tax rate is input, a tax calculation based on the second tax rate is executed, and a fourth value related to the result of the tax calculation based on the second tax rate is stored in the first memory;
The calculator according to any one of claims 2 to 10, further comprising: a read mode setting unit that sets a total sum of the third numerical value and the fourth numerical value in response to input of the first read instruction; and a display unit that displays a total sum of the third numerical value and the fourth numerical value.

[12] The control unit is
When an instruction to execute the first calculation relating to any one of a plurality of tax rates is input, a tax calculation based on the one tax rate is executed, and a numerical value related to the result of the tax calculation based on the one tax rate is stored in the first memory;
In a state where the read mode is set,
A calculator as described in any one of [2] to [11], which displays a total tax by adding up numerical values indicating the results of tax calculations using at least one of the tax rates in response to input of an instruction to execute a function related to any one of the tax rates.

[13] The control unit is
when a third read instruction different from the first read instruction is input while a numerical value indicating a result of the executed first calculation is being displayed on the display unit, the second numerical value stored in the second memory is displayed on the display unit;
13. A calculator as claimed in any one of claims 1 to 12, wherein when the third read instruction is input while a numerical value indicating the result of the executed second calculation is being displayed on the display unit, the first numerical value stored in the first memory is displayed on the display unit.

[14] The control unit is
in response to an input of a tax calculation mode switching instruction, the calculation to be executed as the first calculation is switched between a tax-inclusive calculation and a tax-exclusive calculation;
When the tax-inclusive calculation is executed as the first calculation, the first numerical value is stored in the first memory;
14. The computer according to claim 1, wherein when the first calculation is a tax-excluded calculation, the first numerical value is not stored in the first memory.

[15] By a computer of a computer,
execute a first calculation using numerical values in response to an input of an instruction to execute a first calculation, store a first numerical value relating to the result of the executed first calculation in a first memory and display the first numerical value on a display unit;
execute a second calculation using numerical values in response to an input of an instruction to execute a second calculation different from the first calculation, store a second numerical value related to the result of the executed second calculation in a second memory, and display the second numerical value on the display unit;
when a first read instruction is input while a numerical value indicating a result of the executed first calculation is being displayed on the display unit, the first numerical value stored in the first memory is displayed on the display unit;
A program for causing the display unit to function as follows: when the first read instruction is input while a numerical value indicating the result of the executed second calculation is being displayed on the display unit, the second numerical value stored in the second memory is displayed on the display unit.

[16] A calculation method executed by a control unit of a computer, comprising:
execute a first calculation using numerical values in response to an input of an instruction to execute a first calculation, store a first numerical value relating to the result of the executed first calculation in a first memory and display the first numerical value on a display unit;
execute a second calculation using numerical values in response to an input of an instruction to execute a second calculation different from the first calculation, store a second numerical value related to the result of the executed second calculation in a second memory, and display the second numerical value on the display unit;
when a first read instruction is input while a numerical value indicating a result of the executed first calculation is being displayed on the display unit, the first numerical value stored in the first memory is displayed on the display unit;
A calculation method in which, when the first read instruction is input while a numerical value indicating the result of the executed second calculation is being displayed on the display unit, the second numerical value stored in the second memory is displayed on the display unit.

10...Calculator, 11...Key input section, 11b0...Tax 0 calculation key, 11b1...Tax 1 calculation key, 11b2...Tax 2 calculation key, 11b3...Tax 3 calculation key, 11b4...Tax 4 calculation key, 11c...Tax calculation total key, 11d...Tax calculation mode switching key, 12...Display section, 21...CPU, 22...Memory, 22a...Calculation processing program, 22b...Tax rate 0 total memory area, 22c...Tax rate 1 total memory area, 22d...Tax rate 2 total memory area, 22e...Tax rate 3 total memory area, 22f...Tax rate 4 total memory area, 22g...Tax total memory area, 22h...Total memory area, 22k...Tax total recall mode area, 22m...Tax calculation mode area.

Claims (5)

An electronic device capable of performing tax calculations to derive a tax-inclusive amount, a tax-exclusive amount, or a tax amount as a calculation result,
a storage control means for storing in a predetermined memory a first total value corresponding to the first tax rate and a second total value corresponding to the second tax rate by separating and adding up the calculation results when the instruction to execute the tax calculation is repeated between a case where a first operation key, to which a first tax rate is set, is operated as the instruction to execute the tax calculation following a numerical input, and a case where a second operation key, to which a second tax rate is set, is operated as the instruction to execute the tax calculation following a numerical input;
a display control means for displaying a result of the tax calculation on a predetermined display unit each time the instruction to execute the tax calculation is repeated;
Equipped with
the storage control means stores in the predetermined memory a first total value corresponding to the first tax rate and a second total value corresponding to the second tax rate so that, when a predetermined arithmetic operation is performed during the repetition, a calculation result of the tax calculation performed after the arithmetic operation is summed with a calculation result of the tax calculation performed before the arithmetic operation.
1. An electronic device comprising: When a predetermined arithmetic operation is performed during the repetition, the display control means causes the display unit to display a predetermined mark indicating that the display unit is in a calculation mode in which a calculation result of the tax calculation performed after the arithmetic operation is summed with a calculation result of the tax calculation performed before the arithmetic operation.
2. The electronic device according to claim 1 . the display control means causes the display unit to display a result of the arithmetic operations, and when a third operation key is operated as an instruction to display a total sum obtained by adding up the first sum and the second sum while the result of the arithmetic operations is being displayed on the display unit, causes the display unit to display the total sum instead of the result of the arithmetic operations.
3. The electronic device according to claim 1, wherein the first and second electrodes are electrically connected to the first and second electrodes. A calculation assistance method executed by an electronic device capable of executing tax calculation for deriving a tax-inclusive amount, a tax-exclusive amount, or a tax amount as a calculation result, comprising:
a storage control process for storing in a predetermined memory a first total value corresponding to the first tax rate and a second total value corresponding to the second tax rate by separating and adding up the calculation results when the instruction to execute the tax calculation is repeated between a case where a first operation key, to which a first tax rate is set, is operated as the instruction to execute the tax calculation following a numerical input, and a case where a second operation key, to which a second tax rate is set, is operated as the instruction to execute the tax calculation following a numerical input;
a display control process for displaying a result of the tax calculation on a predetermined display unit each time the instruction to execute the tax calculation is repeated;
Including,
the storage control process stores in the predetermined memory a first total value corresponding to the first tax rate and a second total value corresponding to the second tax rate so that, when a predetermined arithmetic operation is performed during the repetition, a calculation result of the tax calculation performed after the arithmetic operation is summed with a calculation result of the tax calculation performed before the arithmetic operation.
A computational support method comprising: A computer that is an electronic device capable of performing tax calculations to derive a tax-inclusive amount, a tax-exclusive amount, or a tax amount as a result of the calculation;
a storage control means for storing in a predetermined memory a first total value corresponding to the first tax rate and a second total value corresponding to the second tax rate by separating and adding up the calculation results when the instruction to execute the tax calculation is repeated between a case where a first operation key, to which a first tax rate is set, is operated as the instruction to execute the tax calculation following a numerical input, and a case where a second operation key, to which a second tax rate is set, is operated as the instruction to execute the tax calculation following a numerical input;
a display control means for displaying a result of the tax calculation on a predetermined display unit each time the instruction to execute the tax calculation is repeated;
Function as a
the storage control means stores in the predetermined memory a first total value corresponding to the first tax rate and a second total value corresponding to the second tax rate so that, when a predetermined arithmetic operation is performed during the repetition, a calculation result of the tax calculation performed after the arithmetic operation is summed with a calculation result of the tax calculation performed before the arithmetic operation.
A program characterized by: