How do you get the GCF of 325?

Answer 1

The reason you may be finding it difficult is that there's no such thing as the GCF of

one single number. The "C" in the middle stands for "Common", meaning "same for both".

You can't even start looking for the GCF until you have at least two numbers.

Answer 2

Factor them.
3 x 3 = 9
5 x 5 = 25
No common prime factors, the GCF is 1.

Answer 3

By comparing its factors to another set of factors.