Age 5 to 7
Sam, Ben from Matthew Arnold School, and Rohaan from Long Bay Primary School in New Zealand all noticed that you can make a rectangle using any number of dominoes. Here is what Ben said:
It is possible to make a rectangle with any number of dominoes. You simply lay them end to end so that the resulting rectangle gets longer and longer.
Of course, there are lots of more interesting ways to make rectangles; why not try to find some?