DESK ADDITION, SUBTRACTION, MULTIPLICATION, DIVISION COMPUTER WHICH CAN EASILY CHECK ACCOUNTS AND CAN STEADILY EXECUTE CALCULATION WORK

PROBLEM TO BE SOLVED: To recognize the occurrence of the fear of erroneous input when it occurs, to correct it and to restore a system to original calculation by storing an inputted numerical value and an operator to an input history storage memory for every input item, freely displaying them with one keying and recognizing them. SOLUTION: A numerical value and an operator, which are inputted at the time of calculation in a regular calculator mode, are stored in the input history storage memory of a RAM 17 for every input. When a mode switch key 12 is depressed and the system goes to input history display mode, the stored numerical value and the operator can freely be recognized by one keying in an input order direction or a reversed input order direction with an input number and the total number of input items. The stored input history can be corrected by the substitution/deletion/insertion of the numerical value and the operator. Then, the numerical value and the operator, which are stored in the input history storage memory, are sequentially called from the head and are re-calculated and displayed.