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

In Sam and Jill's garden there are two sorts of ladybirds with 7 spots or 4 spots. What numbers of total spots can you make?

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

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

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?

Can you find all the ways to get 15 at the top of this triangle of numbers?

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

What two-digit numbers can you make with these two dice? What can't you make?

What could the half time scores have been in these Olympic hockey matches?

Ten cards are put into five envelopes so that there are two cards in each envelope. The sum of the numbers inside it is written on each envelope. What numbers could be inside the envelopes?

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

In this problem it is not the squares that jump, you do the jumping! The idea is to go round the track in as few jumps as possible.

Tim had nine cards each with a different number from 1 to 9 on it. How could he have put them into three piles so that the total in each pile was 15?

Lolla bought a balloon at the circus. She gave the clown six coins to pay for it. What could Lolla have paid for the balloon?

Roll two red dice and a green dice. Add the two numbers on the red dice and take away the number on the green. What are all the different possibilities that could come up?

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.

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?

Here are some rods that are different colours. How could I make a dark green rod using yellow and white rods?

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

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

Katie had a pack of 20 cards numbered from 1 to 20. She arranged the cards into 6 unequal piles where each pile added to the same total. What was the total and how could this be done?

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?

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?

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?

Can you use the information to find out which cards I have used?

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

An environment which simulates working with Cuisenaire rods.

How could you arrange at least two dice in a stack so that the total of the visible spots is 18?

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.

The computer has made a rectangle and will tell you the number of spots it uses in total. Can you find out where the rectangle is?

This task combines spatial awareness with addition and multiplication.

This challenge combines addition, multiplication, perseverance and even proof.

An investigation involving adding and subtracting sets of consecutive numbers. Lots to find out, lots to explore.

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

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?

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

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

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

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

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?

Here are some short problems for you to try. Talk to your friends about how you work them out.

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

Choose four different digits from 1-9 and put one in each box so that the resulting four two-digit numbers add to a total of 100.

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

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

Amy has a box containing domino pieces but she does not think it is a complete set. She has 24 dominoes in her box and there are 125 spots on them altogether. Which of her domino pieces are missing?

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