Divisibility

  • Plastic human skeleton on a blue background.
    problem

    Skeleton

    Age
    11 to 14
    Challenge level
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    Can you reconstruct the long division calculation from the 'skeleton'?

  • Divisibility Tests
    article

    Divisibility Tests

    This article explains various divisibility rules and why they work. An article to read with pencil and paper handy.

  • Multiple Surprises
    problem
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    Multiple Surprises

    Age
    11 to 16
    Challenge level
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    Sequences of multiples keep cropping up...

  • Take Three From Five
    problem
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    Take Three From Five

    Age
    11 to 16
    Challenge level
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    Caroline and James pick sets of five numbers. Charlie tries to find three that add together to make a multiple of three. Can they stop him?

  • problem
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    Big Powers

    Age
    11 to 16
    Challenge level
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    Three people chose this as a favourite problem. It is the sort of problem that needs thinking time - but once the connection is made it gives access to many similar ideas.

  • Ben's Game
    problem
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    Ben's Game

    Age
    11 to 16
    Challenge level
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    Ben, Jack and Emma passed counters to each other and ended with the same number of counters. How many did they start with?

  • Expenses
    problem
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    Expenses

    Age
    14 to 16
    Challenge level
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    What is the largest number which, when divided into these five numbers in turn, leaves the same remainder each time?

  • Why 24?
    problem
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    Why 24?

    Age
    14 to 16
    Challenge level
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    Take any prime number greater than 3 , square it and subtract one. Working on the building blocks will help you to explain what is special about your results.

  • Knapsack
    problem

    Knapsack

    Age
    14 to 16
    Challenge level
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    You have worked out a secret code with a friend. Every letter in the alphabet can be represented by a binary value.

  • Latin Numbers
    problem
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    Latin Numbers

    Age
    14 to 16
    Challenge level
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    Can you create a Latin Square from multiples of a six digit number?