The greatest common factor (GCF) of 10 and 15 can be found by identifying the factors of each number:
- Factors of 10: 1, 2, 5, 10
- Factors of 15: 1, 3, 5, 15
The common factors are 1 and 5. Therefore, the greatest common factor (GCF) of 10 and 15 is 5.