Mental calculations

There are 106 NRICH Mathematical resources connected to Mental calculations
5 by 5 Mathdokus
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5 by 5 mathdokus

Age
7 to 16
Challenge level
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Can you use the clues to complete these 5 by 5 Mathematical Sudokus?
4 by 4 Mathdokus
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4 by 4 mathdokus

Age
7 to 14
Challenge level
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Can you use the clues to complete these 4 by 4 Mathematical Sudokus?
An Easy Way to Multiply by 10?
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An easy way to multiply by 10?

Age
7 to 11
Challenge level
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Do you agree with Badger's statements? Is Badger's reasoning 'watertight'? Why or why not?
Equivalent Pairs
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Equivalent pairs

Age
5 to 7
Challenge level
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Can you match pairs of cards which show the same amount?
Subtraction Slip
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Subtraction slip

Age
5 to 7
Challenge level
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Can you spot the mistake in this video? How would you work out the answer to this calculation?
Compare the Calculations
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Compare the calculations

Age
7 to 11
Challenge level
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Can you put these four calculations into order of difficulty? How did you decide?
Picture Your Method
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Picture your method

Age
7 to 11
Challenge level
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Can you match these calculation methods to their visual representations?
Fruity Pairs
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Fruity pairs

Age
5 to 7
Challenge level
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Which two items of fruit could Kate and Sam choose? Can you order the prices from lowest to highest?

Tables Teaser
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Tables teaser

Age
5 to 7
Challenge level
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How will you work out which numbers have been used to create this multiplication square?