What is the greatest common factor of 56 and 72?

The GCF of 56 and 72 is 8.

The factors of 56 are 1, 2, 4, 7, 8, 14, 28, and 56

The factors of 72 are 1, 2, 3, 4, 6, 8, 9, 12, 18, 24, 36, and 72

Thus, 8 is the GCF.