A and B are two interlocking cogwheels having p teeth and q teeth respectively. One tooth on B is painted red. Find the values of p and q for which the red tooth on B contacts every gap on the. . . .

The aim of the game is to slide the green square from the top right hand corner to the bottom left hand corner in the least number of moves.

We can show that (x + 1)² = x² + 2x + 1 by considering the area of an (x + 1) by (x + 1) square. Show in a similar way that (x + 2)² = x² + 4x + 4

Use Excel to explore multiplication of fractions.

Use an Excel spreadsheet to explore long multiplication.

Use Excel to practise adding and subtracting fractions.

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

Use an interactive Excel spreadsheet to investigate factors and multiples.

Use Excel to investigate the effect of translations around a number grid.

A simple file for the Interactive whiteboard or PC screen, demonstrating equivalent fractions.

Use an interactive Excel spreadsheet to explore number in this exciting game!

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.

Use an Excel to investigate division. Explore the relationships between the process elements using an interactive spreadsheet.

Can you put the 25 coloured tiles into the 5 x 5 square so that no column, no row and no diagonal line have tiles of the same colour in them?

Do you know how to find the area of a triangle? You can count the squares. What happens if we turn the triangle on end? Press the button and see. Try counting the number of units in the triangle now. . . .

An Excel spreadsheet with an investigation.

Watch this film carefully. Can you find a general rule for explaining when the dot will be this same distance from the horizontal axis?

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

Try entering different sets of numbers in the number pyramids. How does the total at the top change?

When number pyramids have a sequence on the bottom layer, some interesting patterns emerge...

Can you explain the strategy for winning this game with any target?

Triangular numbers can be represented by a triangular array of squares. What do you notice about the sum of identical triangle numbers?

A game for 2 players that can be played online. Players take it in turns to select a word from the 9 words given. The aim is to select all the occurrences of the same letter.

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?

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

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

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

It's easy to work out the areas of most squares that we meet, but what if they were tilted?

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?

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

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....?

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

Players take it in turns to choose a dot on the grid. The winner is the first to have four dots that can be joined to form a square.

Euler discussed whether or not it was possible to stroll around Koenigsberg crossing each of its seven bridges exactly once. Experiment with different numbers of islands and bridges.

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

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

A collection of resources to support work on Factors and Multiples at Secondary level.

The number of plants in Mr McGregor's magic potting shed increases overnight. He'd like to put the same number of plants in each of his gardens, planting one garden each day. How can he do it?

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

What happens when you turn these cogs? Investigate the differences between turning two cogs of different sizes and two cogs which are the same.

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

Meg and Mo need to hang their marbles so that they balance. Use the interactivity to experiment and find out what they need to do.

An interactive activity for one to experiment with a tricky tessellation

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

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 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.