Factoring and Multiples

What is the greatest common factor of 42 and 63?

Answer

Wiki User
11/28/2017

The greatest common factor (GCF) of 42 and 63 is 21.

To find the GCF (greatest common factor) of two numbers, first prime factorize them.

42 = 2*3*7

63 = 3*3*7

The GCF must be able to contain factors such that if divided by 42 or 63, the answer will be an integer.

The GCF is 21.
21

Wiki User
11/29/2009

21.