by Katherine Belsey
Dec 16, 2012
The magic of geometry can teach arithmetic. This little tree frog can multiply, divide, add and subtract as it jumps up and down on a triangle of numbers. No batteries needed for this mechanical calculator!
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Calculating Frog
by Katherine Belsey
Dec 16, 2012
The magic of geometry can teach arithmetic. This little tree frog can multiply, divide, add and subtract as it jumps up and down on a triangle of numbers. No batteries needed for this mechanical calculator!