GCF is 4a^2
First find the GCF of whole numbers 16 and 12
16: 1, 2, 4, 8, 16
12: 1, 2, 3, 4, 6, 12
Gcf of 16 and 12 is 4
Now a^2 and a^4
Just look at the exponents
The highest you can take out of both of them is a^2
Now put the 4 and a^2 together
Answer is 4a^2
