Annie and Ben are playing a game with a calculator. What was Annie's secret number?

There are three buckets each of which holds a maximum of 5 litres. Use the clues to work out how much liquid there is in each bucket.

Use the information about Sally and her brother to find out how many children there are in the Brown family.

The value of the circle changes in each of the following problems. Can you discover its value in each problem?

Claire thinks she has the most sports cards in her album. "I have 12 pages with 2 cards on each page", says Claire. Ross counts his cards. "No! I have 3 cards on each of my pages and there are. . . .

Use the information to work out how many gifts there are in each pile.

Can you work out how many flowers there will be on the Amazing Splitting Plant after it has been growing for six weeks?

There were 22 legs creeping across the web. How many flies? How many spiders?

Twizzle, a female giraffe, needs transporting to another zoo. Which route will give the fastest journey?

Peter, Melanie, Amil and Jack received a total of 38 chocolate eggs. Use the information to work out how many eggs each person had.

These sixteen children are standing in four lines of four, one behind the other. They are each holding a card with a number on it. Can you work out the missing numbers?

These eleven shapes each stand for a different number. Can you use the multiplication sums to work out what they are?

Look on the back of any modern book and you will find an ISBN code. Take this code and calculate this sum in the way shown. Can you see what the answers always have in common?

Throw the dice and decide whether to double or halve the number. Will you be the first to reach the target?

This number has 903 digits. What is the sum of all 903 digits?

This problem is based on the story of the Pied Piper of Hamelin. Investigate the different numbers of people and rats there could have been if you know how many legs there are altogether!

Explore Alex's number plumber. What questions would you like to ask? Don't forget to keep visiting NRICH projects site for the latest developments and questions.

Put operations signs between the numbers 3 4 5 6 to make the highest possible number and lowest possible number.

What happens when you add the digits of a number then multiply the result by 2 and you keep doing this? You could try for different numbers and different rules.

Can you find which shapes you need to put into the grid to make the totals at the end of each row and the bottom of each column?

Can you arrange 5 different digits (from 0 - 9) in the cross in the way described?

Find at least one way to put in some operation signs (+ - x ÷) to make these digits come to 100.

Where can you draw a line on a clock face so that the numbers on both sides have the same total?

On the planet Vuv there are two sorts of creatures. The Zios have 3 legs and the Zepts have 7 legs. The great planetary explorer Nico counted 52 legs. How many Zios and how many Zepts were there?

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?

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

Use your logical reasoning to work out how many cows and how many sheep there are in each field.

EWWNP means Exploring Wild and Wonderful Number Patterns Created by Yourself! Investigate what happens if we create number patterns using some simple rules.

Number problems at primary level that may require resilience.

Number problems at primary level that require careful consideration.

This group activity will encourage you to share calculation strategies and to think about which strategy might be the most efficient.

What do you notice about the date 03.06.09? Or 08.01.09? This challenge invites you to investigate some interesting dates yourself.

A game for 2 people. Use your skills of addition, subtraction, multiplication and division to blast the asteroids.

Here is a picnic that Petros and Michael are going to share equally. Can you tell us what each of them will have?

During the third hour after midnight the hands on a clock point in the same direction (so one hand is over the top of the other). At what time, to the nearest second, does this happen?

If the numbers 5, 7 and 4 go into this function machine, what numbers will come out?

Can you design a new shape for the twenty-eight squares and arrange the numbers in a logical way? What patterns do you notice?

Go through the maze, collecting and losing your money as you go. Which route gives you the highest return? And the lowest?

A game for 2 people using a pack of cards Turn over 2 cards and try to make an odd number or a multiple of 3.

Use your logical-thinking skills to deduce how much Dan's crisps and ice-cream cost altogether.

The Scot, John Napier, invented these strips about 400 years ago to help calculate multiplication and division. Can you work out how to use Napier's bones to find the answer to these multiplications?

How would you count the number of fingers in these pictures?

At the beginning of May Tom put his tomato plant outside. On the same day he sowed a bean in another pot. When will the two be the same height?

Here are the prices for 1st and 2nd class mail within the UK. You have an unlimited number of each of these stamps. Which stamps would you need to post a parcel weighing 825g?

On Friday the magic plant was only 2 centimetres tall. Every day it doubled its height. How tall was it on Monday?

In this article for teachers, Elizabeth Carruthers and Maulfry Worthington explore the differences between 'recording mathematics' and 'representing mathematical thinking'.

Using the statements, can you work out how many of each type of rabbit there are in these pens?