Fractions

  • Harmonic Triangle
    problem
    Favourite

    Harmonic Triangle

    Age
    14 to 16
    Challenge level
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    Can you see how to build a harmonic triangle? Can you work out the next two rows?

  • As Easy as 1,2,3
    problem

    As Easy as 1,2,3

    Age
    11 to 14
    Challenge level
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    When I type a sequence of letters my calculator gives the product of all the numbers in the corresponding memories. What numbers should I store so that when I type 'ONE' it returns 1, and when I type 'TWO' it returns 2, and so on.
  • Bull's Eye
    problem

    Bull's Eye

    Age
    11 to 14
    Challenge level
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    What fractions of the largest circle are the two shaded regions?
  • Racing odds
    problem

    Racing Odds

    Age
    11 to 14
    Challenge level
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    In a race the odds are: 2 to 1 against the rhinoceros winning and 3 to 2 against the hippopotamus winning. What are the odds against the elephant winning if the race is fair?
  • Water lilies
    problem

    Water Lilies

    Age
    11 to 14
    Challenge level
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    There are some water lilies in a lake. The area that they cover doubles in size every day. After 17 days the whole lake is covered. How long did it take them to cover half the lake?
  • Circuit training
    problem

    Circuit Training

    Age
    14 to 16
    Challenge level
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    Mike and Monisha meet at the race track, which is 400m round. Just to make a point, Mike runs anticlockwise whilst Monisha runs clockwise. Where will they meet on their way around and will they ever meet at the start again? If so, after how many circuits?
  • Farthest fraction
    problem

    Farthest Fraction

    Age
    11 to 14
    Challenge level
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    Which of these fractions is the largest?
  • Hexa-split
    problem

    Hexa-Split

    Age
    11 to 14
    Challenge level
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    Which of the areas shown in the hexagons are equal to each other?
  • Couples
    problem

    Couples

    Age
    11 to 14
    Challenge level
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    In a certain community two thirds of the adult men are married to three quarters of the adult women. How many adults would there be in the smallest community of this type?
  • Lower Bound
    problem

    Lower Bound

    Age
    14 to 16
    Challenge level
    filled star filled star empty star
    What would you get if you continued this sequence of fraction sums? 1/2 + 2/1 = 2/3 + 3/2 = 3/4 + 4/3 =