Problem: 1 = 5,2 = 4,3 = 253,4 = 2,6 = 15 , then 15 = ?
Rationale: "1 = 5,2 = 4,3 = 253,4 = 2,6 = 15 , then 15 = ? 15 = 6 check the fifth eqn . answer : e"
annotated_formula: divide(subtract(subtract(15, multiply(multiply(add(const_4, const_2), add(const_4, const_2)), const_10)), 1), const_2)