1. What are the common factors of 14 and 28?
2. What are the common factors of 16 and 32?
3. What are the common factors of 18 and 40?
4. What are the common factors of 8 and 24?
5. What are the common factors of 15 and 18?
6. What are the common factors of 20 and 32?
7. What are the common factors of 18 and 30?
8. What are the common factors of 15, 24 and 30?