What is the greatest common factor of 8 and 20?

The greatest common factor (GCF) of 8 and 20 is 4.

To find the GCF, you can list out the factors of both numbers and find the largest one they have in common:

• Factors of 8: 1, 2, 4, 8
• Factors of 20: 1, 2, 4, 5, 10, 20

The largest factor that both 8 and 20 have in common is 4, so that is their GCF.