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Resources tagged with Addition & subtraction similar to Flashing Lights:

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Broad Topics > Calculations and Numerical Methods > Addition & subtraction

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Four Goodness Sake

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

Use 4 four times with simple operations so that you get the answer 12. Can you make 15, 16 and 17 too?

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Number Juggle

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

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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The Deca Tree

Stage: 2 Challenge Level: Challenge Level:1

Find out what a Deca Tree is and then work out how many leaves there will be after the woodcutter has cut off a trunk, a branch, a twig and a leaf.

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The Clockmaker's Birthday Cake

Stage: 2 Challenge Level: Challenge Level:1

The clockmaker's wife cut up his birthday cake to look like a clock face. Can you work out who received each piece?

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Magic Triangle

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

Place the digits 1 to 9 into the circles so that each side of the triangle adds to the same total.

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Magic Squares 4x4

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

Fill in the numbers to make the sum of each row, column and diagonal equal to 34. For an extra challenge try the huge American Flag magic square.

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Highest and Lowest

Stage: 2 Challenge Level: Challenge Level:1

Put operations signs between the numbers 3 4 5 6 to make the highest possible number and lowest possible number.

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Sam's Quick Sum

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

What is the sum of all the three digit whole numbers?

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The 24 Game

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

There are over sixty different ways of making 24 by adding, subtracting, multiplying and dividing all four numbers 4, 6, 6 and 8 (using each number only once). How many can you find?

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Neighbours

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

In a square in which the houses are evenly spaced, numbers 3 and 10 are opposite each other. What is the smallest and what is the largest possible number of houses in the square?

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Worms

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

Place this "worm" on the 100 square and find the total of the four squares it covers. Keeping its head in the same place, what other totals can you make?

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Largest Number

Stage: 3 Challenge Level: Challenge Level:1

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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Throw a 100

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

Can you score 100 by throwing rings on this board? Is there more than way to do it?

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A Mixed-up Clock

Stage: 2 Challenge Level: Challenge Level:1

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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Being Collaborative - Primary Number

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

Number problems at primary level to work on with others.

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Being Thoughtful - Primary Number

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

Number problems at primary level that require careful consideration.

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Six Is the Sum

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

What do the digits in the number fifteen add up to? How many other numbers have digits with the same total but no zeros?

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Got it for Two

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

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

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Nice or Nasty for Two

Stage: 2 Challenge Level: Challenge Level:1

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

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Being Determined - Primary Number

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

Number problems at primary level that may require determination.

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More Carroll Diagrams

Stage: 2 Challenge Level: Challenge Level:1

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

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Number Tracks

Stage: 2 Challenge Level: Challenge Level:1

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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Napier's Bones

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

The Scot, John Napier, invented these strips about 400 years ago to help calculate multiplication and division. Can you work out how to use Napier's bones to find the answer to these multiplications?

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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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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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Diagonal Sums

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

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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Digit Sum

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

What is the sum of all the digits in all the integers from one to one million?

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Zios and Zepts

Stage: 2 Challenge Level: Challenge Level:1

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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A-magical Number Maze

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

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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Add the Weights

Stage: 2 Challenge Level: Challenge Level:1

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

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How Much Did it Cost?

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

Use your logical-thinking skills to deduce how much Dan's crisps and ice-cream cost altogether.

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Oranges and Lemons

Stage: 2 Challenge Level: Challenge Level:1

On the table there is a pile of oranges and lemons that weighs exactly one kilogram. Using the information, can you work out how many lemons there are?

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X Is 5 Squares

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

Can you arrange 5 different digits (from 0 - 9) in the cross in the way described?

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Adding Plus

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

Can you put plus signs in so this is true? 1 2 3 4 5 6 7 8 9 = 99 How many ways can you do it?

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Buying a Balloon

Stage: 2 Challenge Level: Challenge Level:1

Lolla bought a balloon at the circus. She gave the clown six coins to pay for it. What could Lolla have paid for the balloon?

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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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Dividing a Cake

Stage: 2 Challenge Level: Challenge Level:1

Annie cut this numbered cake into 3 pieces with 3 cuts so that the numbers on each piece added to the same total. Where were the cuts and what fraction of the whole cake was each piece?

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The Number Crunching Machine

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

Put a number at the top of the machine and collect a number at the bottom. What do you get? Which numbers get back to themselves?

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Rocco's Race

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

Rocco ran in a 200 m race for his class. Use the information to find out how many runners there were in the race and what Rocco's finishing position was.

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Amy's Dominoes

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

Amy has a box containing domino pieces but she does not think it is a complete set. She has 24 dominoes in her box and there are 125 spots on them altogether. Which of her domino pieces are missing?

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How Old?

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

Cherri, Saxon, Mel and Paul are friends. They are all different ages. Can you find out the age of each friend using the information?

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Clever Keys

Stage: 2 Short Challenge Level: Challenge Level:1

On a calculator, make 15 by using only the 2 key and any of the four operations keys. How many ways can you find to do it?

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Arranging the Tables

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

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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Next Number

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

Find the next number in this pattern: 3, 7, 19, 55 ...

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Today's Date - 01/06/2009

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

What do you notice about the date 03.06.09? Or 08.01.09? This challenge invites you to investigate some interesting dates yourself.

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Buckets of Thinking

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

There are three buckets each of which holds a maximum of 5 litres. Use the clues to work out how much liquid there is in each bucket.

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Tug Harder!

Stage: 2 Challenge Level: Challenge Level:1

In this game, you can add, subtract, multiply or divide the numbers on the dice. Which will you do so that you get to the end of the number line first?

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Calendar Calculations

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

Try adding together the dates of all the days in one week. Now multiply the first date by 7 and add 21. Can you explain what happens?

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Sept03 Sept03 Sept03

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

This number has 903 digits. What is the sum of all 903 digits?

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Abundant Numbers

Stage: 2 Challenge Level: Challenge Level:1

48 is called an abundant number because it is less than the sum of its factors (without itself). Can you find some more abundant numbers?