An arrangement for adding together two n-digit decimal numbers or subtracting one n-digit decimal number from another comprises 10-condition switch means, the 10 conditions corresponding respectively to digits in the range 0 to 9 to be added or subtracted, and means to determine the need for and to implement the necessary carries.
A tri-property code has been adopted and accordingly combinational and sequential circuits for implementing some arithmetic and logical operations are designed individually then combined into a unit for such operations. Most of the circuits are drawn for the decimal system with general procedures applicable to the other radices.
