Here is a collection of ours - and Libby's - favourite problems which we have enjoyed both at Cambridge and in the classroom!

problem
One basket or group photo
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.

problem
Nine colours
Can you use small coloured cubes to make a 3 by 3 by 3 cube so that each face of the bigger cube contains one of each colour?

problem
Painted cube
Imagine a large cube made from small red cubes being dropped into a pot of yellow paint. How many of the small cubes will have yellow paint on their faces?


problem
Factors and multiples puzzle
Using your knowledge of the properties of numbers, can you fill all the squares on the board?

problem
Your number is...
Think of a number and follow the machine's instructions... I know what your number is! Can you explain how I know?

problem
Number pyramids
Try entering different sets of numbers in the number pyramids. How does the total at the top change?


problem
Tilted squares
It's easy to work out the areas of most squares that we meet, but what if they were tilted?