Question

find the factors of each number. Write the common factor ( CF ) and then state the greatest common factor ( GCF) .

Answer 1

Given:

Two numbers are 12 and 21

To find:

The factors of 12 and 21, then find the common factor and the greatest common factor.

Solution:

Two numbers are 12 and 21. The prime factors of these two numbers are

$12=2\times 2\times 3$

$21=3\times 7$

From the above factorization, it is clear that the factor 3 is common in both. So,

Common factor (CF) = 3

Only 3 is common in factorization of both. So,

Greatest common factor (GCF) = 3

Therefore, the common factor is 3 and the greatest common factor is also 3.