Sum Pyramids – 5
These pyramids are called Sum Pyramids. The number on top is the sum of the two numbers below it.
These pyramids are called Difference Pyramids. The number on top is the difference of the two numbers below.
THE CHALLENGE
Describe how any Sum Pyramid can easily be turned into a Difference Pyramid. Can you find an example of a Difference Pyramid that cannot be easily turned into a Sum Pyramid?
Notes
THE CHALLENGE
To make a Difference Pyramid out of any Sum Pyramid, simply rotate the Sum Pyramid onto its left or right side!
What can go wrong in wanting to turn a Difference Pyramid into a Sum Pyramid, is that the differences may not always go in the same direction. Neither of the following Difference Pyramids can be turned into a Sum Pyramid without a complete rearrangement of the numbers. That’s because they both have a 6 in the middle of a side, and any Sum Pyramid with the numbers 1 to 6 must have the 6 at the tip.
