1. Approaches in a K-12 Classroom for the 21 st Century Mathematics Learners Let’s try this one! Divide the grid along its lines only into two parts The sum of the numbers in one part should be equal to that of the other part.

2. Approaches in a K-12 Classroom for the 21 st Century Mathematics Learners 1 + 2 + 3 + 4 + 5 +7 + 8 + 9 = 39 6 + 10 + 11 + 12 = 39 Answer

3. Approaches in a K-12 Classroom for the 21 st Century Mathematics Learners Using 3 straight lines, divide the circle into regions. The numbers in each region should have equal sums. Lines should begin and end on the circle. They may cross each other, but not the numbers. No empty regions are allowed. Let’s have another!

4. Approaches in a K-12 Classroom for the 21 st Century Mathematics Learners Answer 5 + 1 + 6 = 12 8 + 4 = 12 9 + 3 = 12 2 + 10 = 12 7 + 5 = 12

5. Approaches in a K-12 Classroom for the 21 st Century Mathematics Learners Ready for more? Numbers which make a tree as shown in the diagram observe a certain rule. Which number should be put instead of the question mark?

6. Approaches in a K-12 Classroom for the 21 st Century Mathematics Learners Answer The sum of the digits of the two circles is equal to the number on the third circle Therefore, the resulting number on the circle with the question mark on it is "12". 2+1+3+6 = 12