Abstract: Method for automatically adding scale symbol to operation formula during operation and system for executing the method. The system includes: an input unit for keying in operands and choosing the scale thereof; an input/output buffering unit for temporarily storing the input data; a synchronously checking unit for checking the whether the input operands conform with the scale; a scale symbol adding unit for reading and automatically providing the symbol of the scale and sending the symbol to the input/output buffering unit and a mathematic logic calculating unit to be operated and wait for further instruction. After operated, the data are displayed by an output unit or stored in a memory. The data can be stored in both a read-only memory for check in next use or temporarily stored in a dynamic random access memory for checking the data source of the result and the scale.

Abstract: This invention relates to a method used to zoom in selective plot area in display, which method is inserted an inserted box into the display screen of a display device, and said inserted box can be removed to said display screen anywhere and the plot covered within said inserted box can be zoomed in according to predetermined zoom rate or zoom rate immediately set. Said method of this invention is applicable to a plotting calculator so that by way of keying in the keys of said plotting calculator the user can precisely and quickly select the plot area going to zoom in display.

Abstract: Method for automatically adding scale symbol to operation formula during operation and system for executing the method. The system includes: an input unit for keying in operands and choosing the scale thereof; an input/output buffering unit for temporarily storing the input data; a synchronously checking unit for checking the whether the input operands conform with the scale; a scale symbol adding unit for reading and automatically providing the symbol of the scale and sending the symbol to the input/output buffering unit and a mathematic logic calculating unit to be operated and wait for further instruction. After operated, the data are displayed by an output unit or stored in a memory. The data can be stored in both a read-only memory for check in next use or temporarily stored in a dynamic random access memory for checking the data source of the result and the scale.

Abstract: This invention relates to a method used to zoom in selective plot area in display, which method is inserted an inserted box into the display screen of a display device, and said inserted box can be removed to said display screen anywhere and the plot covered within said inserted box can be zoomed in according to predetermined zoom rate or zoom rate immediately set.

Abstract: The present invention relates a calculator capable of displaying processing status and stopping processing and method of the same. In the present invention, an output unit displays a message representing that the expression is in processing and a counter begins to count after inputting an expression into the calculator. When the counter reaches a first predefined value and the calculation is not finished, a terminating message is shown to inquire the user to choose whether to continue or stop the processing.