Explaining, convincing and proving

  • Triangles in circles
    problem
    Favourite

    Triangles in circles

    Age
    11 to 14
    Challenge level
    filled star empty star empty star

    Can you find triangles on a 9-point circle? Can you work out their angles?

  • Flippin' discs
    problem
    Favourite

    Flippin' discs

    Age
    11 to 14
    Challenge level
    filled star empty star empty star

    Discs are flipped in the air. You win if all the faces show the same colour. What is the probability of winning?

  • Odds and Evens
    problem
    Favourite

    Odds and evens

    Age
    11 to 14
    Challenge level
    filled star empty star empty star

    Are these games fair? How can you tell?

  • problem
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    Reaction timer

    Age
    11 to 14
    Challenge level
    filled star empty star empty star

    This problem offers you two ways to test reactions - use them to investigate your ideas about speeds of reaction.

  • Crossed Ends
    problem
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    Crossed ends

    Age
    11 to 14
    Challenge level
    filled star empty star empty star

    Crosses can be drawn on number grids of various sizes. What do you notice when you add opposite ends?

  • m, m and m
    problem
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    M, M and M

    Age
    11 to 14
    Challenge level
    filled star empty star empty star

    If you are given the mean, median and mode of five positive whole numbers, can you find the numbers?

  • Multiples Sudoku
    problem
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    Multiples Sudoku

    Age
    11 to 14
    Challenge level
    filled star empty star empty star

    Each clue in this Sudoku is the product of the two numbers in adjacent cells.

  • Mixing Lemonade
    problem
    Favourite

    Mixing lemonade

    Age
    11 to 14
    Challenge level
    filled star empty star empty star

    Can you work out which drink has the stronger flavour?

  • problem
    Favourite

    How would you score it?

    Age
    11 to 14
    Challenge level
    filled star empty star empty star

    Invent a scoring system for a 'guess the weight' competition.

  • Sociable Cards
    problem
    Favourite

    Sociable cards

    Age
    11 to 14
    Challenge level
    filled star empty star empty star

    Move your counters through this snake of cards and see how far you can go. Are you surprised by where you end up?