Optical implementation of arithmetic operations using the positional residue system

We present a residue-based method in which the operations of decimal numbers of any magnitude can be processed using only two relatively prime moduli, 2 and 5. We suggest a method of implementation of addition and subtraction using different optical systems. Although the method suffers primarily from the difficulties associated with decimal carrying, we deal with these by means of a separate carry generator that can also be operated in parallel, thus reducing the number of steps.