Question

Find the GCF of 6 and 21

A. 126
B. 21
C. 3
D. None of the above

Answer 1

C. 3

Explanation:

Prime Factorization of 6: 2 × 3

Prime Factorization of 21: 3 × 7

Common Factors of 6 and 21: 3

So the greatest common factor of 6 and 21 is 3, that is, GCF of 6 and 21 is 3.

Answer 2

C. 3

Explanation:

`6 = 2 * 3 \\ \\ 21 = 3 * 7 \\ \\ \because \: common \: factor = 3 \\ \\ \therefore \: gcf \: of \: 6 \: and \: 21 = 3`