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?

Investigate which numbers make these lights come on. What is the smallest number you can find that lights up all the lights?

Can you complete this jigsaw of the multiplication square?

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

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

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

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

There are three versions of this challenge. The idea is to change the colour of all the spots on the grid. Can you do it in fewer throws of the dice?

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

Imagine a wheel with different markings painted on it at regular intervals. Can you predict the colour of the 18th mark? The 100th mark?

Is it possible to place 2 counters on the 3 by 3 grid so that there is an even number of counters in every row and every column? How about if you have 3 counters or 4 counters or....?

This article gives you a few ideas for understanding the Got It! game and how you might find a winning strategy.

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

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

You have 4 red and 5 blue counters. How many ways can they be placed on a 3 by 3 grid so that all the rows columns and diagonals have an even number of red counters?

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

Investigate the smallest number of moves it takes to turn these mats upside-down if you can only turn exactly three at a time.

Interactive game. Set your own level of challenge, practise your table skills and beat your previous best score.

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?

Try to stop your opponent from being able to split the piles of counters into unequal numbers. Can you find a strategy?

In this activity, the computer chooses a times table and shifts it. Can you work out the table and the shift each time?

Can you put the numbers from 1 to 15 on the circles so that no consecutive numbers lie anywhere along a continuous straight line?

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

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

These interactive dominoes can be dragged around the screen.

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

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.

An interactive game to be played on your own or with friends. Imagine you are having a party. Each person takes it in turns to stand behind the chair where they will get the most chocolate.

Can you spot the similarities between this game and other games you know? The aim is to choose 3 numbers that total 15.

A game for 1 or 2 people. Use the interactive version, or play with friends. Try to round up as many counters as possible.

Three beads are threaded on a circular wire and are coloured either red or blue. Can you find all four different combinations?

A game for two people that can be played with pencils and paper. Combine your knowledge of coordinates with some strategic thinking.

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

What are the coordinates of the coloured dots that mark out the tangram? Try changing the position of the origin. What happens to the coordinates now?

An interactive activity for one to experiment with a tricky tessellation

Use the interactivity or play this dice game yourself. How could you make it fair?

Arrange any number of counters from these 18 on the grid to make a rectangle. What numbers of counters make rectangles? How many different rectangles can you make with each number of counters?

Work out the fractions to match the cards with the same amount of money.

Ahmed has some wooden planks to use for three sides of a rabbit run against the shed. What quadrilaterals would he be able to make with the planks of different lengths?

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

Make one big triangle so the numbers that touch on the small triangles add to 10.

How many trains can you make which are the same length as Matt's and Katie's, using rods that are identical?

A train building game for two players. Can you be the one to complete the train?

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

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