This is one of our faves as it always blows our mind! A great visual way to show the power of compound interest – and all you need is a chess or drafts board, and some old coins, or anything you can stack on top of each other really.

The activity: Wizard Chess

Get a couple of big bags of pennies (or anything that’s stackable, like drafts pieces, or small, like rice grains), and a chessboard. Ask your child to put 1p (or 1 grain of rice) on the first square, double it to 2p on the second square, double again to 4p on the third square, and so on. Ask them to estimate how many pennies they will have used by the time they reach the end of the first line on the board, or how many squares they’ll cover before the pennies run out. 


Is they fill the whole board, that would equate to 18,446,744,073,709,551,615 pennies (or grains of rice). So maybe set their expectations!

Take it further

The overall lesson here is to show the power of compound interest (i.e. what happens when you earn interest on top of interest on top of interest etc.) so for older kids you can start to explain that concept to them too (using our guide here). 

Darío Martínez-Batlle

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Got any more activity ideas?

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