Find the GCF of the numbers using an appropriate method.

Question

84 and 126

Find the prime factorization of the number, and write it in exponent form.

198

Answer 1

1) Find the prime factors of each respective number.

84 = 2 x 2 x 3 x 7
126 = 2 x 3 x 3 x 7

Multiply the factors both numbers have in common. In this case multiply 2, 3 and 7.
Therefore, the answer is: 42

2) Again, we will find the prime numbers that go into 198. First divide by the smallest prime number that you can think of that goes easily into 198. I generally start with 2.

198/2 = 99
99/3 = 33
33/3 = 11

Therefore, your answers are 3^2, 2, and 11.

Answer 2

84- 2^2 3 7
126- 2 3^2 7

GCF= 2*3*7= 42

198- 2 3^2 11