Calculating device, calculating method, and computer readable recording medium

A calculating method executed by a processor, the method comprising:

• calculating a payment data item from input calculation data including numerical data items input from at least one of a plurality of numeric keys that are included in a key input unit according to user's operations by a user and operation data items input from at least one of a plurality of operation keys that are included in the key input unit according to operations by the user;
• in response to receiving input of a first deposit data item from at least one of the plurality of numeric keys and input of an instruction of a change function from a change function key included in the key input unit according to operations by the user, controlling a display to display a calculation result data item obtained by subtracting the payment data item from the first deposit data item, as a first change data item;
• and
• in a state where the display displays the first change data item, even through the input calculation data are not re-input, when input of a second deposit data item from at least one of the plurality of numeric keys and input of an instruction of the change function from the change function key according to operations by the user are received, controlling the display to display a calculation result data item obtained by subtracting the payment data item from the second deposit data item, as a second change data item.

A computer readable storage medium retaining a program which is executable in a computer having a key input unit that has a plurality of numeric keys and a plurality of operation keys, a display, and a processor, the plurality of operation keys including a change function key, and the program controlling the processor to perform processes comprising:

• calculating a payment data item from input calculation data including numerical data items input from at least one of the plurality of numeric keys according to operations by a user and operation data items input from at least one of the plurality of operation keys according to operations by the user;
• in response to receiving input of a first deposit data item from at least one of the plurality of numeric keys and input of an instruction of a change function from the change function key according to operations by the user, controlling the display to display a calculation result data item obtained by subtracting the payment data item from the first deposit data item, as a first change data item;
• and
• in a state where the display displays the first change data item, even through the input calculation data are not re-input, when input of a second deposit data item from at least one of the plurality of numeric keys and input of an instruction of the change function from the change function key according to operations by the user are received, controlling the display to display a calculation result data item obtained by subtracting the payment data item from the second deposit data item, as a second change data item.