The GCF is a number or variable you can get out of a equation, the GCF can also be checked to see if its correct by multiplying the GCF with what is left after you got it out
E.J. the GCF of 10 and 25 is 5 because it can fit both in the 10 and the 25 now divide 5 by 10 to get 2 and 5 by 25 to get 5.. Now if you multiply 5 times 2 you get 10 and if you multiply 5 times 5 you get 25, now you can see that that GCF is correct
Hope this helps
