Answer:
The GCF is 3.
Explanation:
All you do is list out the factors of the numbers and find the greatest factor that they have in common.
Like the GCF of 3 and 9. We list the factors.
Factors of 3:
1, 3
Factors of 9:
1, 3, 9
As we can see, 3 is the GCF because it is the highest factor that the numbers have in common.
Hope this helps!