Only one side of a two-slice toaster is working. What is the quickest way to toast both sides of three slices of bread?

Use your addition and subtraction skills, combined with some strategic thinking, to beat your partner at this game.

In this game for two players, the idea is to take it in turns to choose 1, 3, 5 or 7. The winner is the first to make the total 37.

Can you see why 2 by 2 could be 5? Can you predict what 2 by 10 will be?

Can you find all the ways to get 15 at the top of this triangle of numbers? Many opportunities to work in different ways.

How many ways can you find to do up all four buttons on my coat? How about if I had five buttons? Six ...?

Strike it Out game for an adult and child. Can you stop your partner from being able to go?

Ben and his mum are planting garlic. Use the interactivity to help you find out how many cloves of garlic they might have had.

Nim-7 game for an adult and child. Who will be the one to take the last counter?

Got It game for an adult and child. How can you play so that you know you will always win?

This challenge focuses on finding the sum and difference of pairs of two-digit numbers.

This challenge, written for the Young Mathematicians' Award, invites you to explore 'centred squares'.

This article for teachers describes several games, found on the site, all of which have a related structure that can be used to develop the skills of strategic planning.

Find the sum and difference between a pair of two-digit numbers. Now find the sum and difference between the sum and difference! What happens?

An article for teachers and pupils that encourages you to look at the mathematical properties of similar games.

In this problem we are looking at sets of parallel sticks that cross each other. What is the least number of crossings you can make? And the greatest?

A game for 2 players with similarities to NIM. Place one counter on each spot on the games board. Players take it is turns to remove 1 or 2 adjacent counters. The winner picks up the last counter.

Stop the Clock game for an adult and child. How can you make sure you always win this game?

The NRICH team are always looking for new ways to engage teachers and pupils in problem solving. Here we explain the thinking behind maths trails.

Can you work out how to win this game of Nim? Does it matter if you go first or second?

Watch this film carefully. Can you find a general rule for explaining when the dot will be this same distance from the horizontal axis?

This task encourages you to investigate the number of edging pieces and panes in different sized windows.

These tasks give learners chance to generalise, which involves identifying an underlying structure.

Find a route from the outside to the inside of this square, stepping on as many tiles as possible.

This task follows on from Build it Up and takes the ideas into three dimensions!

This is a game for two players. Can you find out how to be the first to get to 12 o'clock?

What happens if you join every second point on this circle? How about every third point? Try with different steps and see if you can predict what will happen.

Sweets are given out to party-goers in a particular way. Investigate the total number of sweets received by people sitting in different positions.

Frances and Rishi were given a bag of lollies. They shared them out evenly and had one left over. How many lollies could there have been in the bag?

It starts quite simple but great opportunities for number discoveries and patterns!

If there are 3 squares in the ring, can you place three different numbers in them so that their differences are odd? Try with different numbers of squares around the ring. What do you notice?

Tom and Ben visited Numberland. Use the maps to work out the number of points each of their routes scores.

Two children made up a game as they walked along the garden paths. Can you find out their scores? Can you find some paths of your own?

This problem challenges you to find out how many odd numbers there are between pairs of numbers. Can you find a pair of numbers that has four odds between them?

Watch this video to see how to roll the dice. Now it's your turn! What do you notice about the dice numbers you have recorded?

This challenge asks you to imagine a snake coiling on itself.

Watch the video of Fran re-ordering these number cards. What do you notice? Try it for yourself. What happens?

In this calculation, the box represents a missing digit. What could the digit be? What would the solution be in each case?

This challenge is about finding the difference between numbers which have the same tens digit.

This challenge encourages you to explore dividing a three-digit number by a single-digit number.

Are these statements relating to odd and even numbers always true, sometimes true or never true?

This article for primary teachers discusses how we can help learners generalise and prove, using NRICH tasks as examples.

Take a look at the video of this trick. Can you perform it yourself? Why is this maths and not magic?

Florence, Ethan and Alma have each added together two 'next-door' numbers. What is the same about their answers?

Watch this animation. What do you see? Can you explain why this happens?

Investigate the sum of the numbers on the top and bottom faces of a line of three dice. What do you notice?

These squares have been made from Cuisenaire rods. Can you describe the pattern? What would the next square look like?

Does this 'trick' for calculating multiples of 11 always work? Why or why not?

Benâ€™s class were cutting up number tracks. First they cut them into twos and added up the numbers on each piece. What patterns could they see?

Try adding together the dates of all the days in one week. Now multiply the first date by 7 and add 21. Can you explain what happens?