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Resources tagged with Addition & subtraction similar to Twenty20:

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Broad Topics > Calculations and Numerical Methods > Addition & subtraction

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Twenty20

Stage: 2, 3 and 4 Challenge Level: Challenge Level:1

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

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4 Dom

Stage: 1, 2, 3 and 4 Challenge Level: Challenge Level:3 Challenge Level:3 Challenge Level:3

Use these four dominoes to make a square that has the same number of dots on each side.

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Domino Square

Stage: 2, 3 and 4 Challenge Level: Challenge Level:2 Challenge Level:2

Use the 'double-3 down' dominoes to make a square so that each side has eight dots.

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Like Powers

Stage: 3 Challenge Level: Challenge Level:1

Investigate $1^n + 19^n + 20^n + 51^n + 57^n + 80^n + 82^n $ and $2^n + 12^n + 31^n + 40^n + 69^n + 71^n + 85^n$ for different values of n.

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As Easy as 1,2,3

Stage: 3 Challenge Level: Challenge Level:1

When I type a sequence of letters my calculator gives the product of all the numbers in the corresponding memories. What numbers should I store so that when I type 'ONE' it returns 1, and when I type. . . .

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Chameleons

Stage: 3 Challenge Level: Challenge Level:1

Whenever two chameleons of different colours meet they change colour to the third colour. Describe the shortest sequence of meetings in which all the chameleons change to green if you start with 12. . . .

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Oddly

Stage: 2 Challenge Level: Challenge Level:3 Challenge Level:3 Challenge Level:3

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

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Score

Stage: 3 Challenge Level: Challenge Level:2 Challenge Level:2

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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Always the Same

Stage: 3 Challenge Level: Challenge Level:3 Challenge Level:3 Challenge Level:3

Arrange the numbers 1 to 16 into a 4 by 4 array. Choose a number. Cross out the numbers on the same row and column. Repeat this process. Add up you four numbers. Why do they always add up to 34?

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Adding and Subtracting Positive and Negative Numbers

Stage: 2, 3 and 4

How can we help students make sense of addition and subtraction of negative numbers?

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The Patent Solution

Stage: 3 Challenge Level: Challenge Level:2 Challenge Level:2

A combination mechanism for a safe comprises thirty-two tumblers numbered from one to thirty-two in such a way that the numbers in each wheel total 132... Could you open the safe?

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An Introduction to Magic Squares

Stage: 1, 2, 3 and 4

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

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Hot Pursuit

Stage: 3 Challenge Level: Challenge Level:2 Challenge Level:2

The sum of the first 'n' natural numbers is a 3 digit number in which all the digits are the same. How many numbers have been summed?

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Aba

Stage: 3 Challenge Level: Challenge Level:2 Challenge Level:2

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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Magic Squares for Special Occasions

Stage: 3 and 4

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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Cubes Within Cubes

Stage: 2 and 3 Challenge Level: Challenge Level:3 Challenge Level:3 Challenge Level:3

We start with one yellow cube and build around it to make a 3x3x3 cube with red cubes. Then we build around that red cube with blue cubes and so on. How many cubes of each colour have we used?

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Arrange the Digits

Stage: 3 Challenge Level: Challenge Level:2 Challenge Level:2

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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Add 3 Dice

Stage: 2, 3 and 4 Challenge Level: Challenge Level:3 Challenge Level:3 Challenge Level:3

Three dice are placed in a row. Find a way to turn each one so that the three numbers on top of the dice total the same as the three numbers on the front of the dice. Can you find all the ways to do. . . .

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Clocked

Stage: 3 Challenge Level: Challenge Level:2 Challenge Level:2

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?

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Eleven

Stage: 3 Challenge Level: Challenge Level:2 Challenge Level:2

Replace each letter with a digit to make this addition correct.

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Cows and Sheep

Stage: 2 Challenge Level: Challenge Level:1

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

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Pyramids

Stage: 3 Challenge Level: Challenge Level:1

What are the missing numbers in the pyramids?

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Tis Unique

Stage: 3 Challenge Level: Challenge Level:1

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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Crossed Ends

Stage: 3 Challenge Level: Challenge Level:1

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

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Dicey Addition

Stage: 1 and 2 Challenge Level: Challenge Level:1

Who said that adding couldn't be fun?

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Pole Star Sudoku 2

Stage: 3 and 4 Challenge Level: Challenge Level:2 Challenge Level:2

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

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Take Three Numbers

Stage: 2 Challenge Level: Challenge Level:1

What happens when you add three numbers together? Will your answer be odd or even? How do you know?

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Countdown Fractions

Stage: 3 and 4 Challenge Level: Challenge Level:1

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

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Calendar Capers

Stage: 3 Challenge Level: Challenge Level:1

Choose any three by three square of dates on a calendar page...

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GOT IT Now

Stage: 2 and 3 Challenge Level: Challenge Level:3 Challenge Level:3 Challenge Level:3

For this challenge, you'll need to play Got It! Can you explain the strategy for winning this game with any target?

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I'm Eight

Stage: 1, 2, 3 and 4 Challenge Level: Challenge Level:1

Find a great variety of ways of asking questions which make 8.

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Top-heavy Pyramids

Stage: 3 Challenge Level: Challenge Level:3 Challenge Level:3 Challenge Level:3

Use the numbers in the box below to make the base of a top-heavy pyramid whose top number is 200.

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Super Value Shapes

Stage: 2 Challenge Level: Challenge Level:1

If each of these three shapes has a value, can you find the totals of the combinations? Perhaps you can use the shapes to make the given totals?

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Make 37

Stage: 2 and 3 Challenge Level: Challenge Level:2 Challenge Level:2

Four bags contain a large number of 1s, 3s, 5s and 7s. Pick any ten numbers from the bags above so that their total is 37.

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Always, Sometimes or Never? Number

Stage: 2 Challenge Level: Challenge Level:1

Are these statements always true, sometimes true or never true?

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Cunning Card Trick

Stage: 3 Challenge Level: Challenge Level:3 Challenge Level:3 Challenge Level:3

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

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Card Trick 2

Stage: 3 Challenge Level: Challenge Level:2 Challenge Level:2

Can you explain how this card trick works?

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Finding Fifteen

Stage: 2 Challenge Level: Challenge Level:2 Challenge Level:2

Tim had nine cards each with a different number from 1 to 9 on it. How could he have put them into three piles so that the total in each pile was 15?

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Weights

Stage: 3 Challenge Level: Challenge Level:2 Challenge Level:2

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

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A Numbered Route

Stage: 2 Challenge Level: Challenge Level:2 Challenge Level:2

Can you draw a continuous line through 16 numbers on this grid so that the total of the numbers you pass through is as high as possible?

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Polo Square

Stage: 2 Challenge Level: Challenge Level:1

Arrange eight of the numbers between 1 and 9 in the Polo Square below so that each side adds to the same total.

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Zargon Glasses

Stage: 2 Challenge Level: Challenge Level:2 Challenge Level:2

Zumf makes spectacles for the residents of the planet Zargon, who have either 3 eyes or 4 eyes. How many lenses will Zumf need to make all the different orders for 9 families?

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One Million to Seven

Stage: 2 Challenge Level: Challenge Level:3 Challenge Level:3 Challenge Level:3

Start by putting one million (1 000 000) into the display of your calculator. Can you reduce this to 7 using just the 7 key and add, subtract, multiply, divide and equals as many times as you like?

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Got it Article

Stage: 2 and 3

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

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Asteroid Blast

Stage: 2 Challenge Level: Challenge Level:2 Challenge Level:2

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

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Odds and Threes

Stage: 2 Challenge Level: Challenge Level:1

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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The Money Maze

Stage: 2 Challenge Level: Challenge Level:1

Go through the maze, collecting and losing your money as you go. Which route gives you the highest return? And the lowest?

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Domino Numbers

Stage: 2 Challenge Level: Challenge Level:2 Challenge Level:2

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

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Lengthy Journeys

Stage: 2 Challenge Level: Challenge Level:1

Investigate the different distances of these car journeys and find out how long they take.

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Oh! Harry!

Stage: 2 Challenge Level: Challenge Level:2 Challenge Level:2

A group of children are using measuring cylinders but they lose the labels. Can you help relabel them?