1. Fill in the numbers 1-6 in each circle so that the sum of the three numbers on each side are equal.

2. The sum of the three sides is either even, or odd. Even: e + e + e e + o + o Odd: o + o + o o + e + e Fill in the numbers 1-6 in each circle so that the sum of the three numbers on each side are equal.

3. Even: e + e + e e + o + o Odd: o + o + o o + e + e Fill in the numbers 1-6 in each circle so that the sum of the three numbers on each side are equal.

4. Even: e + e + e e + o + o Odd: o + o + o o + e + e = 2+4+6 = 12 Fill in the numbers 1-6 in each circle so that the sum of the three numbers on each side are equal.

5. Even: e + e + e= 2+4+6 = 12 Fill in the numbers 1-6 in each circle so that the sum of the three numbers on each side are equal.

6. Even: e + e + e= 2+4+6 = 12 Fill in the numbers 1-6 in each circle so that the sum of the three numbers on each side are equal.

7. Even: e + e + e= 2+4+6 = 12 e + e = o + o 2 4 6 1 5 Fill in the numbers 1-6 in each circle so that the sum of the three numbers on each side are equal.

8. Even: e + e + e= 2+4+6 = 12 e + e = o + o 4 2 6 3 5 Fill in the numbers 1-6 in each circle so that the sum of the three numbers on each side are equal.

9. Even: e + e + e= 2+4+6 = 12 e + e = o + o 2 4 6 1 3 5 Not possible! 2 must be placed in the middle. Fill in the numbers 1-6 in each circle so that the sum of the three numbers on each side are equal.

10. 6 2 4 Even: e + e + e= 2+4+6 = 12 Fill in the numbers 1-6 in each circle so that the sum of the three numbers on each side are equal.

11. 6 2 4 3 1 5 Even: e + e + e= 2+4+6 = 12 Fill in the numbers 1-6 in each circle so that the sum of the three numbers on each side are equal.

12. Even: e + e + e e + o + o Odd: o + o + o o + e + e = 2+4+6 = 12 = 1+3+5 = 9 Fill in the numbers 1-6 in each circle so that the sum of the three numbers on each side are equal.

13. Odd: o + o + o= 1+3+5 = 9 Fill in the numbers 1-6 in each circle so that the sum of the three numbers on each side are equal.

14. e + e = o + o Odd: o + o + o= 1+3+5 = 9 Fill in the numbers 1-6 in each circle so that the sum of the three numbers on each side are equal.

15. e + e = o + o 6 21 5 3 Odd: o + o + o= 1+3+5 = 9 Fill in the numbers 1-6 in each circle so that the sum of the three numbers on each side are equal.

16. e + e = o + o 3 4 2 5 1 Odd: o + o + o= 1+3+5 = 9 Fill in the numbers 1-6 in each circle so that the sum of the three numbers on each side are equal.

17. e + e = o + o 5 1 3 Not possible! 5 must be placed in the middle! Odd: o + o + o= 1+3+5 = 9 6 4 2 Fill in the numbers 1-6 in each circle so that the sum of the three numbers on each side are equal.

18. 1 5 3 Odd: o + o + o= 1+3+5 = 9 Fill in the numbers 1-6 in each circle so that the sum of the three numbers on each side are equal.

19. 1 4 65 23 Odd: o + o + o= 1+3+5 = 9 Fill in the numbers 1-6 in each circle so that the sum of the three numbers on each side are equal.

20. Even: e + e + e e + o + o Odd: o + o + o o + e + e = 2+4+6 = 12 = 1+3+5 = 9 odd at vertex Fill in the numbers 1-6 in each circle so that the sum of the three numbers on each side are equal.

21. e + o = e + o 1 3 5 4 6 Even: e + o + oodd at vertex Fill in the numbers 1-6 in each circle so that the sum of the three numbers on each side are equal.

22. 1 53 Even: e + o + oodd at vertex Fill in the numbers 1-6 in each circle so that the sum of the three numbers on each side are equal.

23. 1 2 46 53 Even: e + o + oodd at vertex Fill in the numbers 1-6 in each circle so that the sum of the three numbers on each side are equal.

24. Even: e + e + e e + o + o Odd: o + o + o o + e + e = 2+4+6 = 12 = 1+3+5 = 9 odd at vertex even at vertex Fill in the numbers 1-6 in each circle so that the sum of the three numbers on each side are equal.

25. e + o = o + e 2 4 6 3 5 Odd: o + e + eeven at vertex Fill in the numbers 1-6 in each circle so that the sum of the three numbers on each side are equal.

26. 2 35 64 Odd: o + e + eeven at vertex Fill in the numbers 1-6 in each circle so that the sum of the three numbers on each side are equal.

27. 2 1 35 64 Odd: o + e + eeven at vertex Fill in the numbers 1-6 in each circle so that the sum of the three numbers on each side are equal.

28. 6 3 21 45 1 4 65 23 1 2 46 53 2 1 35 64 Fill in the numbers 1-6 in each circle so that the sum of the three numbers on each side are equal.

29. Choosing numbers randomly does not quickly lead to an answer. Solving the problem requires reasoning and simple computations. Prerequisites: Addition & Subtraction; Understanding of even and odd numbers. The problem is cracked when students deduce additional facts from the limited information provided.