What is the greatest common factor of 20 and 48?

The GCF of 20 and 48 is 4.

The factors of 20 are 1, 2, 4, 5, 10, and 20

The factors of 48 are 1, 2, 3, 4, 6, 8, 12, 16, 24, and 48

So the GCF of 20 and 48 is 4.