Explaining, convincing and proving

  • The Dangerous Ratio
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    The Dangerous Ratio

    This article for pupils and teachers looks at a number that even the great mathematician, Pythagoras, found terrifying.

  • Pythagorean Triples I
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    Pythagorean Triples I

    The first of two articles on Pythagorean Triples which asks how many right angled triangles can you find with the lengths of each side exactly a whole number measurement. Try it!

  • Pythagorean Triples II
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    Pythagorean Triples II

    This is the second article on right-angled triangles whose edge lengths are whole numbers.

  • The Frieze Tree
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    The Frieze Tree

    Patterns that repeat in a line are strangely interesting. How many types are there and how do you tell one type from another?

  • Impossible Sandwiches
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    Impossible Sandwiches

    In this 7-sandwich: 7 1 3 1 6 4 3 5 7 2 4 6 2 5 there are 7 numbers between the 7s, 6 between the 6s etc. The article shows which values of n can make n-sandwiches and which cannot.

  • Mouhefanggai
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    Mouhefanggai

    Imagine two identical cylindrical pipes meeting at right angles and think about the shape of the space which belongs to both pipes. Early Chinese mathematicians call this shape the mouhefanggai.

  • Symmetric Tangles
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    Symmetric Tangles

    The tangles created by the twists and turns of the Conway rope trick are surprisingly symmetrical. Here's why!

  • A Knight's Journey
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    A Knight's Journey

    This article looks at knight's moves on a chess board and introduces you to the idea of vectors and vector addition.