This project challenges you to work out the number of cubes hidden under a cloth. What questions would you like to ask?

Ahmed is making rods using different numbers of cubes. Which rod is twice the length of his first rod?

Make one big triangle so the numbers that touch on the small triangles add to 10. You could use the interactivity to help you.

Jack's mum bought some candles to use on his birthday cakes and when his sister was born, she used them on her cakes too. Can you use the information to find out when Kate was born?

If you have ten counters numbered 1 to 10, how many can you put into pairs that add to 10? Which ones do you have to leave out? Why?

Can you find 2 butterflies to go on each flower so that the numbers on each pair of butterflies adds to the same number as the one on the flower?

An environment which simulates working with Cuisenaire rods.

Place the numbers 1 to 6 in the circles so that each number is the difference between the two numbers just below it.

This big box adds something to any number that goes into it. If you know the numbers that come out, what addition might be going on in the box?

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

Use the number weights to find different ways of balancing the equaliser.

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

Sam got into an elevator. He went down five floors, up six floors, down seven floors, then got out on the second floor. On what floor did he get on?

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

Try grouping the dominoes in the ways described. Are there any left over each time? Can you explain why?

Can you hang weights in the right place to make the equaliser balance?

Ram divided 15 pennies among four small bags. He could then pay any sum of money from 1p to 15p without opening any bag. How many pennies did Ram put in each bag?

On Planet Plex, there are only 6 hours in the day. Can you answer these questions about how Arog the Alien spends his day?

Can you each work out the number on your card? What do you notice? How could you sort the cards?

Find your way through the grid starting at 2 and following these operations. What number do you end on?

As you come down the ladders of the Tall Tower you collect useful spells. Which way should you go to collect the most spells?

Can you each work out the number on your card? What do you notice? How could you sort the cards?

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

Fill in the numbers to make the sum of each row, column and diagonal equal to 15.

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

Make your own double-sided magic square. But can you complete both sides once you've made the pieces?

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

Find all the numbers that can be made by adding the dots on two dice.

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

Dotty Six is a simple dice game that you can adapt in many ways.

Using the cards 2, 4, 6, 8, +, - and =, what number statements can you make?

Woof is a big dog. Yap is a little dog. Emma has 16 dog biscuits to give to the two dogs. She gave Woof 4 more biscuits than Yap. How many biscuits did each dog get?

Are these statements relating to calculation and properties of shapes always true, sometimes true or never true?

Can you arrange fifteen dominoes so that all the touching domino pieces add to 6 and the ends join up? Can you make all the joins add to 7?

There were chews for 2p, mini eggs for 3p, Chocko bars for 5p and lollypops for 7p in the sweet shop. What could each of the children buy with their money?

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. . . .

There are three baskets, a brown one, a red one and a pink one, holding a total of 10 eggs. Can you use the information given to find out how many eggs are in each basket?

If you hang two weights on one side of this balance, in how many different ways can you hang three weights on the other side for it to be balanced?

There are to be 6 homes built on a new development site. They could be semi-detached, detached or terraced houses. How many different combinations of these can you find?

Use these head, body and leg pieces to make Robot Monsters which are different heights.

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

Leah and Tom each have a number line. Can you work out where their counters will land? What are the secret jumps they make with their counters?

On a farm there were some hens and sheep. Altogether there were 8 heads and 22 feet. How many hens were there?

Use these four dominoes to make a square that has the same number of dots on each side.

Arrange the numbers 1 to 6 in each set of circles below. The sum of each side of the triangle should equal the number in its centre.