Find the Greatest Common Factor (GCF) of 12 and 18. Study the solution below. Method 1: By listing the factors of 12 and 18 Factors of 12: 1,2,3,4,6, and 12 Factors of 18: 1,2,3,6,9, and 18 By finding the common factors of 12 and 18 Common factors of 12 and 18: 1.2,3 and 6