Estimating and approximating

  • Growing
    problem

    Growing

    Age
    16 to 18
    Challenge level
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    Which is larger: (a) 1.000001^{1000000} or 2? (b) 100^{300} or 300! (i.e.factorial 300)
  • Squaring the circle
    problem

    Squaring the Circle

    Age
    11 to 14
    Challenge level
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    Bluey-green, white and transparent squares with a few odd bits of shapes around the perimeter. But, how many squares are there of each type in the complete circle? Study the picture and make an estimate.
  • Archimedes and numerical roots
    problem

    Archimedes and Numerical Roots

    Age
    14 to 16
    Challenge level
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    The problem is how did Archimedes calculate the lengths of the sides of the polygons which needed him to be able to calculate square roots?
  • Branching Processes and Extinction
    problem

    Branching Processes and Extinction

    Age
    16 to 18
    Challenge level
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    An advanced mathematical exploration supporting our series of articles on population dynamics for advanced students.
  • Today's date - 01/06/2009
    problem

    Today's Date - 01/06/2009

    Age
    5 to 11
    Challenge level
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    What do you notice about the date 03.06.09? Or 08.01.09? This challenge invites you to investigate some interesting dates yourself.
  • What's My Weight?
    problem

    What's My Weight?

    Age
    7 to 11
    Challenge level
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    There are four equal weights on one side of the scale and an apple on the other side. What can you say that is true about the apple and the weights from the picture?
  • Back to School
    problem

    Back to School

    Age
    7 to 11
    Challenge level
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    Mr. Sunshine tells the children they will have 2 hours of homework. After several calculations, Harry says he hasn't got time to do this homework. Can you see where his reasoning is wrong?
  • Four Go for Two
    game

    Four Go for Two

    Age
    7 to 11
    Challenge level
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    Four Go game for an adult and child. Will you be the first to have four numbers in a row on the number line?