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A $2$ by $3$ rectangle contains $8$ squares. Can you see how?

A $3$ by $4$ rectangle contains $20$ squares. Can you see how?

A $4$ by $6$ rectangle contains $50$ squares. Can you see how?

What size rectangle contains exactly $100$ squares?

Is there more than one?

Can you find them all?

Can you prove that there are no more?

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