What is the gcf of 12 and 18?

The greatest common factor (GCF) of 12 and 18 is 6. This is the largest number that divides both 12 and 18 without leaving a remainder. The factors of 12 are 1, 2, 3, 4, 6, and 12, while the factors of 18 are 1, 2, 3, 6, 9, and 18. The GCF is the highest factor that appears in both lists, which in this case is 6.