What is the greatest common factor of 15 and 10?

The greatest common factor (GCF) of two numbers is the largest number that divides both of them without leaving a remainder.

To find the GCF of 15 and 10, we can factor each number:

15 = 3 x 5 10 = 2 x 5

The common factors of 15 and 10 are 1 and 5. However, the greatest common factor is 5 since it is the largest number that divides both 15 and 10 without leaving a remainder.

Therefore, the GCF of 15 and 10 is 5.