4 2 3 1 math answer July 8, 2019 16 32 64 128 5 4 3 2 1 math challenge answers 5 4 3 2 1 math challenge answer key pdf 5 4 3 2 1 math challenge answer key 1 2 + 3 4 1 2 3 4 challenge 1 + 2 + 3 + 4 = 10 + 1 + 2 + 3 + 4 + 5
