This Sudoku, based on differences. Using the one clue number can you find the solution?

Use the differences to find the solution to this Sudoku.

This Sudoku requires you to do some working backwards before working forwards.

Got It game for an adult and child. How can you play so that you know you will always win?

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

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

Make your own double-sided magic square. But can you complete both sides once you've made the pieces?

If you take a three by three square on a 1-10 addition square and multiply the diagonally opposite numbers together, what is the difference between these products. Why?

Can you find six numbers to go in the Daisy from which you can make all the numbers from 1 to a number bigger than 25?

The letters in the following addition sum represent the digits 1 ... 9. If A=3 and D=2, what number is represented by "CAYLEY"?

By selecting digits for an addition grid, what targets can you make?

Do you notice anything about the solutions when you add and/or subtract consecutive negative numbers?

How many solutions can you find to this sum? Each of the different letters stands for a different number.

Delight your friends with this cunning trick! Can you explain how it works?

Find the values of the nine letters in the sum: FOOT + BALL = GAME

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

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

The country Sixtania prints postage stamps with only three values 6 lucres, 10 lucres and 15 lucres (where the currency is in lucres).Which values cannot be made up with combinations of these postage. . . .

Crosses can be drawn on number grids of various sizes. What do you notice when you add opposite ends?

15 = 7 + 8 and 10 = 1 + 2 + 3 + 4. Can you say which numbers can be expressed as the sum of two or more consecutive integers?

Five numbers added together in pairs produce: 0, 2, 4, 4, 6, 8, 9, 11, 13, 15 What are the five numbers?

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

Is it possible to rearrange the numbers 1,2......12 around a clock face in such a way that every two numbers in adjacent positions differ by any of 3, 4 or 5 hours?

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

This article explains how to make your own magic square to mark a special occasion with the special date of your choice on the top line.

Special clue numbers related to the difference between numbers in two adjacent cells and values of the stars in the "constellation" make this a doubly interesting problem.

A cinema has 100 seats. Show how it is possible to sell exactly 100 tickets and take exactly £100 if the prices are £10 for adults, 50p for pensioners and 10p for children.

Add or subtract the two numbers on the spinners and try to complete a row of three. Are there some numbers that are good to aim for?

This challenging activity involves finding different ways to distribute fifteen items among four sets, when the sets must include three, four, five and six items.

Find out about Magic Squares in this article written for students. Why are they magic?!

There are exactly 3 ways to add 4 odd numbers to get 10. Find all the ways of adding 8 odd numbers to get 20. To be sure of getting all the solutions you will need to be systematic. What about. . . .

Using the 8 dominoes make a square where each of the columns and rows adds up to 8

Ann thought of 5 numbers and told Bob all the sums that could be made by adding the numbers in pairs. The list of sums is 6, 7, 8, 8, 9, 9, 10,10, 11, 12. Help Bob to find out which numbers Ann was. . . .

Charlie has made a Magic V. Can you use his example to make some more? And how about Magic Ls, Ns and Ws?

Investigate the different ways that fifteen schools could have given money in a charity fundraiser.

In the following sum the letters A, B, C, D, E and F stand for six distinct digits. Find all the ways of replacing the letters with digits so that the arithmetic is correct.

This challenge extends the Plants investigation so now four or more children are involved.

Three children are going to buy some plants for their birthdays. They will plant them within circular paths. How could they do this?

An investigation involving adding and subtracting sets of consecutive numbers. Lots to find out, lots to explore.

What happens when you add a three digit number to its reverse?

Fancy a game of cricket? Here is a mathematical version you can play indoors without breaking any windows.

Try out some calculations. Are you surprised by the results?

There are nasty versions of this dice game but we'll start with the nice ones...

Some Games That May Be Nice or Nasty for an adult and child. Use your knowledge of place value to beat your opponent.

How many ways can you find to put in operation signs (+ - x ÷) to make 100?

Can you arrange the digits 1,2,3,4,5,6,7,8,9 into three 3-digit numbers such that their total is close to 1500?