Explaining, convincing and proving

  • Pythagoras Proofs
    problem
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    Pythagoras Proofs

    Age
    11 to 16
    Challenge level
    2 out of 3

    Can you make sense of these three proofs of Pythagoras' Theorem?

  • problem
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    Shopping Basket

    Age
    11 to 16
    Challenge level
    3 out of 3

    The items in the shopping basket add and multiply to give the same amount. What could their prices be?

  • Common Divisor
    problem
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    Common Divisor

    Age
    14 to 16
    Challenge level
    1 out of 3

    Find the largest integer which divides every member of the following sequence: 1^5-1, 2^5-2, 3^5-3, ... n^5-n.

  • How old am I?
    problem
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    How Old Am I?

    Age
    14 to 16
    Challenge level
    1 out of 3

    In 15 years' time my age will be the square of my age 15 years ago. Can you work out my age, and when I had other special birthdays?

  • Chances are
    problem
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    Chances Are

    Age
    14 to 16
    Challenge level
    1 out of 3

    Which of these games would you play to give yourself the best possible chance of winning a prize?

  • problem
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    Salinon

    Age
    14 to 16
    Challenge level
    1 out of 3

    This shape comprises four semi-circles. What is the relationship between the area of the shaded region and the area of the circle on AB as diameter?

  • The Better Choice
    problem
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    The Better Choice

    Age
    14 to 16
    Challenge level
    1 out of 3

    Here are two games you can play. Which offers the better chance of winning?

  • Where is the dot?
    problem
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    Where Is the Dot?

    Age
    14 to 16
    Challenge level
    1 out of 3

    A dot starts at the point (1,0) and turns anticlockwise. Can you estimate the height of the dot after it has turned through 45 degrees? Can you calculate its height?

  • Making sixty
    problem
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    Making Sixty

    Age
    14 to 16
    Challenge level
    1 out of 3

    Why does this fold create an angle of sixty degrees?

  • Curvy areas
    problem
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    Curvy Areas

    Age
    14 to 16
    Challenge level
    1 out of 3

    Have a go at creating these images based on circles. What do you notice about the areas of the different sections?