Solution: The Penny Penning Challenge
The Penny Penning Challenge asked students to draw four “pens” around the nine pennies in a three by three array in such a way that there were an odd number of pennies in each pen. There is no way to divide nine objects into four separate sets of odd numbers since any combination of four odd numbers produces an even sum. Therefore, to solve this puzzle students had to think divergently and realize that in any solution, one or more of the pens must overlap. When this insight has been made, there are several valid solutions to the puzzle. One of these solutions is shown below.
