Have lots of counters, blocks or coloured bits of paper ready so the children can experiment with combinations. This problem has quite a few solutions, so the children will quickly become muddled if they don't record each solution as it's found. Be prepared for a discussion as to whether rotated solutions are different or not.

/fig2.gif">

When children think they have found all the solutions, ask them to prove it! This may mean rearranging their solutions systematically to check for missing answers.

One extension would be to ask the children to find any squares that could be repeated to make a patchwork quilt, without placing two squares of the same colour together.