Addition and subtraction

problem
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Number Pyramids

Age

11 to 14

Challenge level

1 out of 3

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

Age

11 to 14

Challenge level

1 out of 3

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?
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Magic Letters

Age

11 to 14

Challenge level

1 out of 3

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

Age

11 to 14

Challenge level

1 out of 3

Imagine a very strange bank account where you are only allowed to do two things...
game
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Up, Down, Flying Around

Age

11 to 14

Challenge level

1 out of 3

Play this game to learn about adding and subtracting positive and negative numbers
problem
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Number Daisy

Age

11 to 14

Challenge level

1 out of 3

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?
problem
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Cryptarithms

Age

11 to 14

Challenge level

1 out of 3

Can you crack these cryptarithms?
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Add to 200

Age

11 to 14

Challenge level

1 out of 3

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

Age

11 to 14

Challenge level

1 out of 3

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

Age

11 to 14

Challenge level

1 out of 3

How many different differences can you make?