Problem: how many multiples of 3 are there between 5 and 59 , 5 and 59 inclusive ?
Rationale: "3 multiples are . . . 6,9 , 12,15 , 18,21 , 24,27 , 30,33 , 36,39 , 42,45 , 48,51 , 54,57 , . . . , the answer is = 18 answer is c"
annotated_formula: add(divide(subtract(59, 5), 3), const_1)