In mathematics science, subtraction is rather simple computation of arithmetic. However, no matter what advanced computer in the world, and no matter what backward calculator (such as abacus in China etc.) in people’s hand, to get difference of subtraction is always a NP problem in all the time. Such as capacities of numbers Minuend and Subtrahend, symbols (±) of number value (positive number or negative number), precise computing (PC), computing precision (CP), perturbation motion (PM) in computing of numbers, etc. This paper makes an algorithm of novel subtraction with AI-VCR computation in computer, and gives solutions of avoiding the difference’s overflowing, insufficient valid figures, etc.