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Tangrams

Can you make five differently sized squares from the interactive tangram pieces?

Polydron

This activity investigates how you might make squares and pentominoes from Polydron.

Construct-o-straws

Make a cube out of straws and have a go at this practical challenge.

Cuisenaire Squares

Age 7 to 11
Challenge Level
You could use some Cuisenaire rods to have a go at this problem or you could use this interactivity.
Alternatively, drawing rods on squared paper might help.