Greatest Common Factor

Nicole
Middle 7th Student

What is the Greatest Common Facter for:

126,261
1008,1080
546,1995
128,256
and
255,256

Thanks!!!!!!!

Hi Nicole,

To find the Greatest Common Factor (GCF) of each pair of numbers it is probably best to first find the prime factorization of each number. For example for 126 and 261

126 = 2 x 3² x 7
261 = 3² x 29 Find the highest power of each prime that divdes both numbers and then the product of these powers is the GCF. For 126 and 261 only 3 divides both numbers and the highest power of 3 that divides tham both is 2. Thus GCF(126, 261) = 3² = 9

You can find a few more examples in the answer we gave Debbie to a similar question.

Cheers,
Penny Go to Math Central