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? Many opportunities to work in different ways.

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

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

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?

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?

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 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.

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

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

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

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?

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

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.

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 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?

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?

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

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 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?

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

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?

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.

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?

An environment which simulates working with Cuisenaire rods.

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

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

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

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

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

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?

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

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

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

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

This task combines spatial awareness with addition and multiplication.

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?

Four bags contain a large number of 1s, 3s, 5s and 7s. Pick any ten numbers from the bags above so that their total is 37.

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

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