Geometric sequences

  • Magic Plant
    problem
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    Magic Plant

    Age
    5 to 7
    Challenge level
    2 out of 3

    On Friday the magic plant was only 2 centimetres tall. Every day it doubled its height. How tall was it on Monday?

  • problem
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    The Amazing Splitting Plant

    Age
    5 to 7
    Challenge level
    3 out of 3

    Can you work out how many flowers there will be on the Amazing Splitting Plant after it has been growing for six weeks?

  • The tomato and the bean
    problem
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    The Tomato and the Bean

    Age
    5 to 7
    Challenge level
    3 out of 3

    At the beginning of May, Tom put his tomato plant outside. On the same day he sowed a bean in another pot. When will the two be the same height?

  • Pocket money
    problem
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    Pocket Money

    Age
    11 to 14
    Challenge level
    1 out of 3

    Which of these pocket money systems would you rather have?

  • The Tower of Hanoi - three wooden poles, with several coloured rings of decreasing sizes on the middle pole.
    problem
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    Tower of Hanoi

    Age
    11 to 14
    Challenge level
    2 out of 3

    The Tower of Hanoi is an ancient mathematical challenge. Working on the building blocks may help you to explain the patterns you notice.

  • Double Trouble
    problem
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    Double Trouble

    Age
    14 to 16
    Challenge level
    1 out of 3

    Simple additions can lead to intriguing results...

  • Tiny Nines
    problem
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    Tiny Nines

    Age
    14 to 16
    Challenge level
    2 out of 3

    What do you notice about these families of recurring decimals?

  • Summing geometric progressions
    problem
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    Summing Geometric Progressions

    Age
    14 to 18
    Challenge level
    1 out of 3

    Watch the video to see how to sum the sequence. Can you adapt the method to sum other sequences?

  • Sixty-Seven Squared
    problem
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    Sixty-Seven Squared

    Age
    16 to 18
    Challenge level
    1 out of 3

    Evaluate these powers of 67. What do you notice? Can you convince someone what the answer would be to (a million sixes followed by a 7) squared?

  • Clickety Click and all the Sixes
    problem
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    Clickety Click and All the Sixes

    Age
    16 to 18
    Challenge level
    1 out of 3
    What is the sum of: 6 + 66 + 666 + 6666 ............+ 666666666...6 where there are n sixes in the last term?