Visualising and representing

  • Getting an angle
    problem

    Getting an Angle

    Age
    11 to 14
    Challenge level
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    How can you make an angle of 60 degrees by folding a sheet of paper twice?

  • Cubist Cuts
    problem

    Cubist Cuts

    Age
    11 to 14
    Challenge level
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    A 3×3×3 cube may be reduced to unit cubes in six saw cuts. If after every cut you can rearrange the pieces before cutting straight through, can you do it in fewer?

  • Convex Polygons
    problem

    Convex Polygons

    Age
    11 to 14
    Challenge level
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    Show that among the interior angles of a convex polygon there cannot be more than three acute angles.

  • Hello Again
    problem

    Hello Again

    Age
    11 to 14
    Challenge level
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    Anne completes a circuit around a circular track in 40 seconds. Brenda runs in the opposite direction and meets Anne every 15 seconds. How long does it take Brenda to run around the track?

  • Hexagon Cut Out
    problem

    Hexagon Cut Out

    Age
    11 to 14
    Challenge level
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    Weekly Problem 52 - 2012
    An irregular hexagon can be made by cutting the corners off an equilateral triangle. How can an identical hexagon be made by cutting the corners off a different equilateral triangle?

  • Revolutions
    problem

    Revolutions

    Age
    11 to 14
    Challenge level
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    Jack and Jill run at different speeds in opposite directions around the maypole. How many times do they pass in the first minute?

  • The Cantor Set
    problem

    The Cantor Set

    Age
    11 to 14
    Challenge level
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    Take a line segment of length 1. Remove the middle third. Remove the middle thirds of what you have left. Repeat infinitely many times, and you have the Cantor Set. Can you picture it?

  • 17s and 23s
    problem

    17s and 23s

    Age
    11 to 14
    Challenge level
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    Can you form this 2010-digit number...

  • Crawl Around the Cube
    problem

    Crawl Around the Cube

    Age
    11 to 14
    Challenge level
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    Weekly Problem 37 - 2010
    An ant is crawling around the edges of a cube. From the description of his path, can you predict when he will return to his starting point?