### Why do this problem?

This activity is good for engaging pupils in number patterns, symmetry, factors, multiples, algebra and shape work, and allows them to be creative. It should also encourage pupils to persevere for a longer period of time than perhaps is usual.

### Possible approach

Beware that when children are counting or communicating generally about what they've done there is a tendency to count the number on each side of a shape inaccurately. In this example:

... there is the confusion of counting $4$ on each side and then multiplying by $6$, instead of counting the "new ones" each time and saying that there are $3$ new ones on each side.

Having dotty square and triangular paper available may help the children. Just let them enjoy this and see what opportunities arise!