Try grouping the dominoes in the ways described. Are there any left over each time? Can you explain why?
Have a good look at these images. Can you describe what is happening? There are plenty more images like this on NRICH's Exploring Squares CD.
Can you put the numbers from 1 to 15 on the circles so that no consecutive numbers lie anywhere along a continuous straight line?
This was a problem for our birthday website. Can you use four of these pieces to form a square? How about making a square with all five pieces?
Find out why these matrices are magic. Can you work out how they were made? Can you make your own Magic Matrix?
Kaia is sure that her father has worn a particular tie twice a week in at least five of the last ten weeks, but her father disagrees. Who do you think is right?
An investigation involving adding and subtracting sets of consecutive numbers. Lots to find out, lots to explore.
Libby Jared helped to set up NRICH and this is one of her favourite problems. It's a problem suitable for a wide age range and best tackled practically.