What is the greatest common factor of 105 and147?

Answer 1

To find the greatest common factor of two numbers, you first need to break those numbers down into their prime factors. For 105 and 147 this is:

105 = 3x5x7

147 = 3x7x7

The next step is to identify any common prime factors. In this case, both numbers have a 3 as a prime factor, and a 7 as a prime factor. Multiply these together to get the GCF:

3x7 = 21

Thus the greatest common factor of 105 and 147 is 21.