radix-minus-one complement

A number obtained by subtracting each digit of a given number from one less than the radix of that digit position, one at a time. Note 1: In the decimal numeration system, the radix is ten (10). The radix minus one (1) is nine (9). The radix-minus-one complement of decimal 496 is 503, obtained by subtracting each digit from 9. The radix-minus-one complement of pure binary 1101 is 0010, obtained by subtracting each digit from 1, or simply by reversing each digit. Note 2:In a bank of flip-flops, a given number and its radix-minus-one complement are both always present for use in arithmetic operations. To set a register to all 1s, add any number in the register to its radix-minus-one complement. To set it to all 0s, add 1 to the previous result and propagate all the carries. To subtract two numbers, add the radix-minus-one complement of the subtrahend to the minuend and add 1 to the result, propagating all the carries. The most significant digit has to be deleted if an additional digit...