Question

What is the gcf of 378,132

Answer 1

First, find the prime factorization of both numbers.

378/2 = 189
189/3 = 63
63/3 = 21
21/3 = 7
7/7 1

378 = 2 * 3^3 * 7

132/2 = 66
66/2 = 33
33/3 = 11
11/11 = 1

132 = 2^2 * 3 * 11

For the GCF, choose the common factors with lower exponent.

378 = 2 * 3^3 * 7
132 = 2^2 * 3 * 11

From 2 and 2^2 choose 2.
From 3 and 3^2 choose 3.
7 and 11 are not common, so do not choose them.

GCF = 2 * 3 = 6