What is the gcf of 72 and 126?

Answer 1

72 = 2 x 2 x 2 x 3 x 3

126 = 2 x 2 x 3 x 7

The common prime factors are 2, 2, and 3.

Therefore the greatest common factor is 2 x 2 x 3 = 12

Answer 2

18