What is the greatest common factor of 22 and 40?

Answer 1

The factors of 22 are 1, 2, 11, and 22.

The factors of 40 are 1, 2, 4, 5, 8, 10, 20, and 40.

The largest factor they have in common is 2, therefore 2 is the greatest common factor.

Or, you can use the prime factors to determine the greatest common factor.

The prime factors of 22 are 2 and 11.

The prime factors of 40 are 2, 2, 2, and 5.

The prime factors they have in common are a single 2, so 2 is the greatest common factor.
The GCF is 2.