Creating and manipulating expressions and formulae

  • Folding in Half
    problem

    Folding in Half

    Age
    14 to 16
    Challenge level
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    How does the perimeter change when we fold this isosceles triangle in half?

  • Packing Boxes
    problem

    Packing Boxes

    Age
    14 to 16
    Challenge level
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    Look at the times that Harry, Christine and Betty take to pack boxes when working in pairs, to find how fast Christine can pack boxes by herself.

  • Diophantine n-tuples
    problem

    Diophantine N-Tuples

    Age
    14 to 16
    Challenge level
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    Can you explain why a sequence of operations always gives you perfect squares?

  • DOTS Division
    problem

    DOTS Division

    Age
    14 to 16
    Challenge level
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    Take any pair of two digit numbers x=ab and y=cd where, without loss of generality, ab > cd . Form two 4 digit numbers r=abcd and s=cdab and calculate: {r^2 - s^2} /{x^2 - y^2}.

  • There and back
    problem

    There and Back

    Age
    14 to 16
    Challenge level
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    Brian swims at twice the speed that a river is flowing, downstream from one moored boat to another and back again, taking 12 minutes altogether. How long would it have taken him in still water?

  • Series Sums
    problem

    Series Sums

    Age
    14 to 16
    Challenge level
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    Let S1 = 1 , S2 = 2 + 3, S3 = 4 + 5 + 6 ,........ Calculate S17.

  • The Pillar of Chios
    problem

    The Pillar of Chios

    Age
    14 to 16
    Challenge level
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    Semicircles are drawn on the sides of a rectangle. Prove that the sum of the areas of the four crescents is equal to the area of the rectangle.

  • AMGM
    problem

    AMGM

    Age
    14 to 16
    Challenge level
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    Can you use the diagram to prove the AM-GM inequality?

  • Really Mr. Bond
    problem

    Really Mr. Bond

    Age
    14 to 16
    Challenge level
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    Can you explain what's happening with these numbers?

  • A Tilted Square
    problem

    A Tilted Square

    Age
    14 to 16
    Challenge level
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    The opposite vertices of a square have coordinates (a,b) and (c,d). What are the coordinates of the other vertices?