What is the process for getting the GCF of 16 and 20?

Answer 1

The factors of 16 are:

1, 2, 4, 8, 16

The factors of 20 are:

1, 2, 4, 5, 10, 20

The common factors are:

1, 2, 4

The Greatest Common Factor:

GCF = 4

Answer 2

For small numbers such as these, you might use prime factoring. Get the prime factors of 16 and 20, and see which factors they have in common. Multiply these factors in common among themselves (if there is more than one prime factor in common), to get the answer.