What is the greatest common factor of 12 and 20?

The greatest common factor (GCF) of 12 and 20 is 4. This is the largest number that divides evenly into both 12 and 20.

To find the GCF, you can list all of the factors of each number and then identify the largest factor that they have in common.

The factors of 12 are 1, 2, 3, 4, 6, and 12. The factors of 20 are 1, 2, 4, 5, 10, and 20.

The largest factor that both 12 and 20 share is 4, so the GCF of 12 and 20 is 4.