What is the greatest common factor of 12 40 and 68?

To find the greatest common factor (GCF) of 12, 40, and 68, we first need to find the factors of each number. The factors of 12 are 1, 2, 3, 4, 6, and 12. The factors of 40 are 1, 2, 4, 5, 8, 10, 20, and 40. The factors of 68 are 1, 2, 4, 17, 34, and 68. The greatest common factor among these three numbers is 4.