How do You Find the Gcf?

The GCF or the greatest common factor of two or more numbers can be found by either listing all the factors of the numbers and seeing which is the greatest factor that is common to these numbers, or to use prime factorization. For numbers like 12 and 15, it might be easy to list factors to find the GCF, but for large numbers, like 240 and 276, it might be better to use prime factorization. If you list the factors for 12, these are 1, 2, 3, 4, 6, 12, and for 15 they are 1, 3, 5, 15. The GCF for 12 and 15 is 3. You can find more information here: