If you are a teacher click here for a version of the problem suitable for classroom use, together with supporting materials. Otherwise, read on ...

Nine squares with side lengths $1, 4, 7, 8, 9, 10, 14, 15$ and $18$ cm can be fitted together with no gaps and no overlaps, to form a rectangle.

What are the dimensions of the rectangle?

Once you've had a chance to think about it, click below to see how three different pupils began working on the task.

This is how Anna started:

Here is what Brendan tried:

Here is Chandra's initial approach to the problem:

Can you take each of these starting ideas and develop them into a solution?