What is the greatest common factor of 84 72 24?

Since 72 is a multiple of 24, and the greatest common factor cannot be greater than the smallest number, the greatest common factor of 84, 72, and 24 will be the greatest common factor of 84 and 24.

The factors of 84 are 1, 2, 3, 4, 6, 7, 12, 14, 21, 28, 42, and 84.

The factors of 24 are 1, 2, 3, 4, 6, 8, 12, and 24.

(The factors of 72 are 1, 2, 3, 4, 6, 8, 9, 12, 18, 24, 36, and 72.)

The greatest common factor is 12.

Or, you can look at the prime factors.

The prime factors of 84 are 2, 2, 3, and 7.

The prime factors of 24 are 2, 2, 2, and 3.

(The prime factors of 72 are 2, 2, 2, 3, and 3.)

The prime factors they have in common are 2, 2, and 3, so the greatest common factor is 2 x 2 x 3 = 12.