What is the greatest common factor of 72 and 100?

The greatest common factor is the highest number that divides exactly into two or more numbers.

72: 1, 2, 3, 4, 6, 8, 9, 12, 18, 24, 36, 72

100: 1, 2, 4, 5, 10, 20, 25, 50, 100

The GCF for 72 and 100 is 4.