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Resources tagged with Addition & subtraction similar to Coded Hundred Square:

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Challenge level: Challenge Level:1 Challenge Level:2 Challenge Level:3

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Broad Topics > Calculations and Numerical Methods > Addition & subtraction

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Spell by Numbers

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

Can you substitute numbers for the letters in these sums?

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Difference

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

Place the numbers 1 to 10 in the circles so that each number is the difference between the two numbers just below it.

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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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A Square of Numbers

Stage: 2 Challenge Level: Challenge Level:1

Can you put the numbers 1 to 8 into the circles so that the four calculations are correct?

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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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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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Pouring the Punch Drink

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

There are 4 jugs which hold 9 litres, 7 litres, 4 litres and 2 litres. Find a way to pour 9 litres of drink from one jug to another until you are left with exactly 3 litres in three of the jugs.

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Code Breaker

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

This problem is based on a code using two different prime numbers less than 10. You'll need to multiply them together and shift the alphabet forwards by the result. Can you decipher the code?

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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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Sealed Solution

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

Ten cards are put into five envelopes so that there are two cards in each envelope. The sum of the numbers inside it is written on each envelope. What numbers could be inside the envelopes?

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Twenty Divided Into Six

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

Katie had a pack of 20 cards numbered from 1 to 20. She arranged the cards into 6 unequal piles where each pile added to the same total. What was the total and how could this be done?

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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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Dodecamagic

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

Here you see the front and back views of a dodecahedron. Each vertex has been numbered so that the numbers around each pentagonal face add up to 65. Can you find all the missing numbers?

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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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Seven Square Numbers

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

Add the sum of the squares of four numbers between 10 and 20 to the sum of the squares of three numbers less than 6 to make the square of another, larger, number.

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Bean Bags for Bernard's Bag

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

How could you put eight beanbags in the hoops so that there are four in the blue hoop, five in the red and six in the yellow? Can you find all the ways of doing this?

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Brothers and Sisters

Stage: 2 Challenge Level: Challenge Level:1

Cassandra, David and Lachlan are brothers and sisters. They range in age between 1 year and 14 years. Can you figure out their exact ages from the clues?

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Money Bags

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

Ram divided 15 pennies among four small bags. He could then pay any sum of money from 1p to 15p without opening any bag. How many pennies did Ram put in each bag?

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Page Numbers

Stage: 2 Short Challenge Level: Challenge Level:1

Exactly 195 digits have been used to number the pages in a book. How many pages does the book have?

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Magic Circles

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

Put the numbers 1, 2, 3, 4, 5, 6 into the squares so that the numbers on each circle add up to the same amount. Can you find the rule for giving another set of six numbers?

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Prison Cells

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

There are 78 prisoners in a square cell block of twelve cells. The clever prison warder arranged them so there were 25 along each wall of the prison block. How did he do it?

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Ladybird Box

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

Place six toy ladybirds into the box so that there are two ladybirds in every column and every row.

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Plants

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

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

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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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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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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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On Target

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

You have 5 darts and your target score is 44. How many different ways could you score 44?

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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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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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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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Five Coins

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

Ben has five coins in his pocket. How much money might he have?

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The Puzzling Sweet Shop

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

There were chews for 2p, mini eggs for 3p, Chocko bars for 5p and lollypops for 7p in the sweet shop. What could each of the children buy with their money?

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Shapes in a Grid

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

Can you find which shapes you need to put into the grid to make the totals at the end of each row and the bottom of each column?

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Follow the Numbers

Stage: 2 Challenge Level: Challenge Level:1

What happens when you add the digits of a number then multiply the result by 2 and you keep doing this? You could try for different numbers and different rules.

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It Was 2010!

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

If the answer's 2010, what could the question be?

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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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Dicey Addition

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

Who said that adding couldn't be fun?

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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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Sitting Round the Party Tables

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

Sweets are given out to party-goers in a particular way. Investigate the total number of sweets received by people sitting in different positions.

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Fifteen Cards

Stage: 2 Challenge Level: Challenge Level:1

Can you use the information to find out which cards I have used?

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Build it up More

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

This task follows on from Build it Up and takes the ideas into three dimensions!

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Build it Up

Stage: 2 Challenge Level: Challenge Level:1

Can you find all the ways to get 15 at the top of this triangle of numbers?

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The Dice Train

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

This dice train has been made using specific rules. How many different trains can you make?

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Sums and Differences 2

Stage: 2 Challenge Level: Challenge Level:1

Find the sum and difference between a pair of two-digit numbers. Now find the sum and difference between the sum and difference! What happens?

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Sums and Differences 1

Stage: 2 Challenge Level: Challenge Level:1

This challenge focuses on finding the sum and difference of pairs of two-digit numbers.

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Rabbits in the Pen

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

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

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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?

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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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Totality

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

This is an adding game for two players.

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Prompt Cards

Stage: 2 Challenge Level: Challenge Level:1

These two group activities use mathematical reasoning - one is numerical, one geometric.