These problems provide an opportunity to see if the children can work logically and to organise information in a systematic way.

Providing opportunities for the youngest learners to learn the classic problem solving strategies is very important to helping children develop and internalise problem-solving skills. Using a matrix to organise information is a wonderful tool for solving logic problems. In this way, children are able to isolate helpful pieces of information and discard what is extraneous.

In this problem, it is likely that they will pick their favourite shirt and trousers and start from there and randomly match one garment with another. It is worth raising the point that 'new' does not mean 'clean' (!) - each item can be worn more than once provided it is part of a different combination.

But how can they tell if they have all possible combinations? This is the vital question.

The problem can be printed off and young learners can cut out the clothes and match them in the various combinations. But how will the results be recorded? It may be more appropriate for younger learners to draw each of the combinations. Children who are able to deal with a more abstract representation should be encouraged to consider how many different shirts for each pair of trousers and to draw a matrix, or grid, to show the possible combinations.