Play this game and see if you can figure out the computer's chosen number.

Do you know a quick way to check if a number is a multiple of two? How about three, four or six?

A game for two people, or play online. Given a target number, say 23, and a range of numbers to choose from, say 1-4, players take it in turns to add to the running total to hit their target.

A game in which players take it in turns to choose a number. Can you block your opponent?

Imagine we have four bags containing a large number of 1s, 4s, 7s and 10s. What numbers can we make?

Play the divisibility game to create numbers in which the first two digits make a number divisible by 2, the first three digits make a number divisible by 3...

A country has decided to have just two different coins, 3z and 5z coins. Which totals can be made? Is there a largest total that cannot be made? How do you know?

Take any four digit number. Move the first digit to the end and move the rest along. Now add your two numbers. Did you get a multiple of 11?

Think of a two digit number, reverse the digits, and add the numbers together. Something special happens...

Different combinations of the weights available allow you to make different totals. Which totals can you make?

Where should you start, if you want to finish back where you started?

Can you find a relationship between the number of dots on the circle and the number of steps that will ensure that all points are hit?

Can you guarantee that, for any three numbers you choose, the product of their differences will always be an even number?

How many different lengths is it possible to measure with a set of three rods?

This article takes the reader through divisibility tests and how they work. An article to read with pencil and paper to hand.

Here is a machine with four coloured lights. Can you develop a strategy to work out the rules controlling each light?

The clues for this Sudoku are the product of the numbers in adjacent squares.

Can you find out what is special about the dimensions of rectangles you can make with squares, sticks and units?

Caroline and James pick sets of five numbers. Charlie chooses three of them that add together to make a multiple of three. Can they stop him?

Can you explain what is going on in these puzzling number tricks?