What is the greatest common factor of 63 and 108?

Factors of 108 are 1, 2, 3, 4, 6, 9, 12, 18, 27, 36, 54, and 108

Factors of 63 are 1, 3, 7, 9, 21, 63

The GCF of 108 and 63 is 9