when 1 / 10 % of 4,000 is subtracted from 1 / 10 of 4,000 , the difference is
"1 / 10 % of 4000 = 4 1 / 10 of 4000 = 400 400 - 4 = 396 ans : c"
multiply(inverse(10), multiply(multiply(const_100, 10), add(const_4, const_4)))