when 1 / 20 % of 4,000 is subtracted from 1 / 20 of 4,000 , the difference is
"1 / 20 % of 4000 = 2 1 / 20 of 4000 = 200 200 - 2 = 198 ans : b"
multiply(inverse(20), multiply(multiply(const_100, 20), add(const_4, const_4)))