Question

What is the gcf of 54 and 90

Answer 1

The greatest common factor of 54 and 90 is 18

Answer 2

The prime factorization of 54 is 2 * $3^{3}$
The prime factorization of 90 is 2 * $3^{2}$ * 5
What do they have in common? 2 * 3², which is 18.