Addition and subtraction

There are 355 NRICH Mathematical resources connected to Addition and subtraction
Ordering cards
problem
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Ordering cards

Age
5 to 11
Challenge level
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This problem is designed to help children to learn, and to use, the two and three times tables.
Doing and undoing
problem
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Doing and undoing

Age
5 to 11
Challenge level
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An investigation looking at doing and undoing mathematical operations focusing on doubling, halving, adding and subtracting.
How do you see it?
problem
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How do you see it?

Age
5 to 11
Challenge level
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Here are some short problems for you to try. Talk to your friends about how you work them out.

Magic Letters
problem
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Magic letters

Age
11 to 14
Challenge level
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Charlie has made a Magic V. Can you use his example to make some more? And how about Magic Ls, Ns and Ws?
Two numbers under the microscope
problem
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Two numbers under the microscope

Age
5 to 7
Challenge level
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This investigates one particular property of number by looking closely at an example of adding two odd numbers together.
Take three numbers
problem
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Take three numbers

Age
7 to 11
Challenge level
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What happens when you add three numbers together? Will your answer be odd or even? How do you know?

Fifteen cards
problem
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Fifteen cards

Age
7 to 11
Challenge level
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Can you use the information to find out which cards I have used?
Summing Consecutive Numbers
problem
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Summing consecutive numbers

Age
11 to 14
Challenge level
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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?

Half Time
problem
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Half time

Age
5 to 11
Challenge level
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What could the half time scores have been in these Olympic hockey matches?
Number Pyramids
problem
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Number pyramids

Age
11 to 14
Challenge level
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Try entering different sets of numbers in the number pyramids. How does the total at the top change?