First, write out the prime factorization of both 12 and 80: 12 = 2 x 2 x 3 and 80 = 2 x 2 x 2 x 2 x 5. Now collect only the prime numbers that each of them share in their factorizations, which are only two 2's. Thus, the greatest common factor between 12 and 80 is 2 x 2 = 4. Step-by-step explanation:
