Problem: find the simple interest on $ 10000 at 7 % per annum for 12 months ?
Rationale: "p = $ 10000 r = 7 % t = 12 / 12 years = 1 year s . i . = p * r * t / 100 = 10000 * 7 * 1 / 100 = $ 700 answer is d"
annotated_formula: multiply(10000, divide(7, const_100))