#### Answer

4

#### Work Step by Step

The GCF of 12 and 32 is 6.
To find, find the prime factors of each term.
12's factors are -12, -6, -4,-3,-2,-1,1,2,3,4,6, and 12.
For 32, they are -32, -16, -8, -4, -2, -1, 1, 2, 4, 8, 16, and 32.
Look for the common factors. They are -4,-2,-1,1,2, and 4.
The biggest one is 4, so that is the answer.