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

Choose four of the numbers from 1 to 9 to put in the squares so that the differences between joined squares are odd.

Can you put the numbers 1 to 8 into the circles so that the four calculations are correct?

Start by putting one million (1 000 000) into the display of your calculator. Can you reduce this to 7 using just the 7 key and add, subtract, multiply, divide and equals as many times as you like?

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

Use the interactivities to fill in these Carroll diagrams. How do you know where to place the numbers?

Can you work out how to balance this equaliser? You can put more than one weight on a hook.

Place the numbers from 1 to 9 in the squares below so that the difference between joined squares is odd. How many different ways can you do this?

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

How many different ways can you find to join three equilateral triangles together? Can you convince us that you have found them all?

How many different triangles can you draw on the dotty grid which each have one dot in the middle?

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

Use the interactivity to help get a feel for this problem and to find out all the possible ways the balls could land.

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

Place the numbers 1 to 10 in the circles so that each number is the difference between the two numbers just below it.

This 100 square jigsaw is written in code. It starts with 1 and ends with 100. Can you build it up?

Can you use the numbers on the dice to reach your end of the number line before your partner beats you?

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?

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

Move just three of the circles so that the triangle faces in the opposite direction.

Use the interactivity to find out how many quarter turns the man must rotate through to look like each of the pictures.

Have a go at this well-known challenge. Can you swap the frogs and toads in as few slides and jumps as possible?

An environment which simulates working with Cuisenaire rods.

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?

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

Here is a chance to play a version of the classic Countdown Game.

Starting with the number 180, take away 9 again and again, joining up the dots as you go. Watch out - don't join all the dots!

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?

What does the overlap of these two shapes look like? Try picturing it in your head and then use the interactivity to test your prediction.

Can you make a train the same length as Laura's but using three differently coloured rods? Is there only one way of doing it?

How have the numbers been placed in this Carroll diagram? Which labels would you put on each row and column?

If you have only four weights, where could you place them in order to balance this equaliser?

In your bank, you have three types of coins. The number of spots shows how much they are worth. Can you choose coins to exchange with the groups given to make the same total?

Arrange the four number cards on the grid, according to the rules, to make a diagonal, vertical or horizontal line.

This problem is based on a code using two different prime numbers less than 10. You'll need to multiply them together and shift the alphabet forwards by the result. Can you decipher the code?

Complete the squares - but be warned some are trickier than they look!

Can you make the green spot travel through the tube by moving the yellow spot? Could you draw a tube that both spots would follow?

What do the numbers shaded in blue on this hundred square have in common? What do you notice about the pink numbers? How about the shaded numbers in the other squares?

Can you sort these triangles into three different families and explain how you did it?

Place six toy ladybirds into the box so that there are two ladybirds in every column and every row.

An interactive activity for one to experiment with a tricky tessellation

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

A game to be played against the computer, or in groups. Pick a 7-digit number. A random digit is generated. What must you subract to remove the digit from your number? the first to zero wins.

How many different rhythms can you make by putting two drums on the wheel?

A game for 2 people that everybody knows. You can play with a friend or online. If you play correctly you never lose!