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Find the sum of all three-digit numbers each of whose digits is odd.

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

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

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

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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. . . .

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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?

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

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

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A game for 2 people using a pack of cards Turn over 2 cards and try to make an odd number or a multiple of 3.

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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. . . .

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Choose two digits and arrange them to make two double-digit numbers. Now add your double-digit numbers. Now add your single digit numbers. Divide your double-digit answer by your single-digit answer. . . .

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

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Try out this number trick. What happens with different starting numbers? What do you notice?

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Make a set of numbers that use all the digits from 1 to 9, once and once only. Add them up. The result is divisible by 9. Add each of the digits in the new number. What is their sum? Now try some. . . .

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

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.

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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?

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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?

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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.

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This addition sum uses all ten digits 0, 1, 2...9 exactly once. Find the sum and show that the one you give is the only possibility.

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A game for 2 or more players with a pack of cards. Practise your skills of addition, subtraction, multiplication and division to hit the target score.

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This magic square has operations written in it, to make it into a maze. Start wherever you like, go through every cell and go out a total of 15!

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In this 100 square, look at the green square which contains the numbers 2, 3, 12 and 13. What is the sum of the numbers that are diagonally opposite each other? What do you notice?

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Ben’s class were cutting up number tracks. First they cut them into twos and added up the numbers on each piece. What patterns could they see?

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Number problems at primary level that may require resilience.

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A game for 2 people. Use your skills of addition, subtraction, multiplication and division to blast the asteroids.

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

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What is the largest number you can make using the three digits 2, 3 and 4 in any way you like, using any operations you like? You can only use each digit once.

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

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Using the statements, can you work out how many of each type of rabbit there are in these pens?

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

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Number problems at primary level to work on with others.

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Use your logical reasoning to work out how many cows and how many sheep there are in each field.

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There are 44 people coming to a dinner party. There are 15 square tables that seat 4 people. Find a way to seat the 44 people using all 15 tables, with no empty places.

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

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Fill in the missing numbers so that adding each pair of corner numbers gives you the number between them (in the box).

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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?

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

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On the planet Vuv there are two sorts of creatures. The Zios have 3 legs and the Zepts have 7 legs. The great planetary explorer Nico counted 52 legs. How many Zios and how many Zepts were there?

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In this simulation of a balance, you can drag numbers and parts of number sentences on to the trays. Have a play!

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There is a clock-face where the numbers have become all mixed up. Can you find out where all the numbers have got to from these ten statements?

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Without doing lots of calculations, can you decide which of these number sentences are true? How do you know?

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

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

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