what is the gcf of 12 and 20

The GCF (Greatest Common Factor) of 12 and 20 is 4. One way to find the GCF is to compare the prime factorization of each number. The prime factorization of 12 is 2^2 x 3, and the prime factorization of 20 is 2^2 x 5. The common factors are 2^2, which is equal to 4, and this is the largest number that evenly divides into both 12 and 20. Therefore, the GCF of 12 and 20 is 4.