Personal calculator e.g. office calculator, for use by accountant, has control unit controlling red, blue, yellow, orange and green light emitting diodes, respectively following different lighting states, according to arithmetic operations

摘要

The calculator has a keyboard (14) with keys for entering arithmetic operations to be carried out. A central processing unit controls the display of the results of operations input from the keyboard, on a display screen (16). A control unit controls red, blue, yellow, orange and green light emitting diodes, respectively following different lighting states, according to the arithmetic operations, where the diodes light the calculator.