Mr Gilderdale is playing a game with his class. What rule might he have chosen? How would you test your idea?

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

Twenty four games for the run-up to Christmas.

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

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

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

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

Choose 13 spots on the grid. Can you work out the scoring system? What is the maximum possible score?

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

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

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?

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!

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

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

Take it in turns to place a domino on the grid. One to be placed horizontally and the other vertically. Can you make it impossible for your opponent to play?

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

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

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

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

Each light in this interactivity turns on according to a rule. What happens when you enter different numbers? Can you find the smallest number that lights up all four lights?

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?

First Connect Three game for an adult and child. Use the dice numbers and either addition or subtraction to get three numbers in a straight line.

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

Incey Wincey Spider game for an adult and child. Will Incey get to the top of the drainpipe?

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

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

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....?

How many right angles can you make using two sticks?

This was a problem for our birthday website. Can you use four of these pieces to form a square? How about making a square with all five pieces?

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

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

Yasmin and Zach have some bears to share. Which numbers of bears can they share so that there are none left over?

The idea of this game is to add or subtract the two numbers on the dice and cover the result on the grid, trying to get a line of three. Are there some numbers that are good to aim for?

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?

Use the interactivity to sort these numbers into sets. Can you give each set a name?

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

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

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

An interactive game for 1 person. You are given a rectangle with 50 squares on it. Roll the dice to get a percentage between 2 and 100. How many squares is this? Keep going until you get 100. . . .

A game for 2 players. Can be played online. One player has 1 red counter, the other has 4 blue. The red counter needs to reach the other side, and the blue needs to trap the red.

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 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.

A game for 2 people that can be played on line or with pens and paper. Combine your knowledege of coordinates with your skills of strategic thinking.