Fill in the blanks with the correct number.

1. 6 + 4 = 1 + ___

2. 5 + 1 = 6 + ___

3. 10 + 4 = 4 + ___

4. 10 + 10 = 5 + ___

5. 13 + ___ = 14 + 1

6. 5 + ___ = 6 + 5

7. 8 + 9 = 1 + ___

8. 5 + 4 = 2 + ___

9. 4 + 10 = 1 + ___

10. 9 + 4 = 3 + ___

11. 1 + ___ = 4 + 6

12. 4 + ___ = 2 + 10

13. ___ + 1 = 6 + 2

14. 1 + 1 = ___ + 2

15. 7 + 8 = 5 + ___

16. 6 + 4 = 8 + ___