Have a go at this well-known challenge. Can you swap the frogs and toads in as few slides and jumps as possible?
This challenge is a game for two players. Choose two numbers from the grid and multiply or divide, then mark your answer on the number line. Can you get four in a row before your partner?
You have been given three shapes made out of sponge: a sphere, a cylinder and a cone. Your challenge is to find out how to cut them to make different shapes for printing.
Skippy and Anna are locked in a room in a large castle. The key to that room, and all the other rooms, is a number. The numbers are locked away in a problem. Can you help them to get out?
Follow this recipe for sieving numbers and see what interesting patterns emerge.
Can you find rectangles where the value of the area is the same as the value of the perimeter?
Try entering different sets of numbers in the number pyramids. How does the total at the top change?
When number pyramids have a sequence on the bottom layer, some interesting patterns emerge...
Several of you from different schools clearly explained how you
used the charts to sort out the data.
Go to last month's problems to see more solutions.
Here we look back at the year with NRICH and suggest mathematical summer holiday activities for students, parents and teachers.