Reasoning, convincing and proving

There are 458 NRICH Mathematical resources connected to Reasoning, convincing and proving
Six Ten Total
problem

Six Ten Total

Age
7 to 11
Challenge level
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This challenge combines addition, multiplication, perseverance and even proof.
Multiplication arithmagons
problem

Multiplication arithmagons

Age
14 to 16
Challenge level
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Can you find the values at the vertices when you know the values on the edges of these multiplication arithmagons?
Reversals
problem

Reversals

Age
11 to 14
Challenge level
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Where should you start, if you want to finish back where you started?
Pythagoras Perimeters
problem

Pythagoras Perimeters

Age
14 to 16
Challenge level
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If you know the perimeter of a right angled triangle, what can you say about the area?
Difference of Two Squares
problem

Difference of Two Squares

Age
14 to 16
Challenge level
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What is special about the difference between squares of numbers adjacent to multiples of three?
Impossibilities
problem

Impossibilities

Age
11 to 14
Challenge level
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Just because a problem is impossible doesn't mean it's difficult...
Cryptarithms
problem

Cryptarithms

Age
11 to 14
Challenge level
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Can you crack these cryptarithms?
Overlaps
problem

Overlaps

Age
11 to 14
Challenge level
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Can you find ways to put numbers in the overlaps so the rings have equal totals?