# Coin Conundrums

Here’s a neat brain teaser that helps your preschooler learn on multiple levels. You can use it to teach about coin denominations, counting, and shape recognition and formation, plus there’s a puzzle to solve! Travis was a bit frustrated at first, but so proud when he cracked the code for the final teaser.

For each of these three teasers, all you need is pennies (or any other coin). Travis counted out six pennies for the first one.

I set the pennies up in a triangle, with the point away from Travis. Could we move only two pennies so the point was facing toward him instead?

At first he just randomly dragged two pennies.

I prompted him to try moving the bottom two pennies up, and voila, our triangle was reversed. Now he was intrigued!

Next we counted out four pennies and put them in a line. Could we make it so each penny was touching all the others? Squares didn’t work, or diamond shapes, or lines.

Turns out you can’t think in one dimension for this one! The key is to build up, with one penny poised atop the other (touching) three.

Finally, we counted out nine pennies, and I arranged them in a large triangle. Could Travis figure out how to turn this into a square, moving only two pennies?

We identified that the shape toward the middle was nearly square already.

Carefully, he tried moving one of the bottom pennies up. Now he could see the square forming, and complete the final move without any help.

Voila!

We got these ideas from Highlights; can you think of other penny brain teasers? Please share in the comments.