Indices

  • Public Key Cryptography
    article

    Public key cryptography

    An introduction to coding and decoding messages and the maths behind how to secretly share information.
  • Age of Augustus
    problem

    Age of augustus

    Age
    11 to 14
    Challenge level
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    The English mathematician Augustus de Morgan has given his age in algebraic terms. Can you work out when he was born?
  • Maundy Money
    problem

    Maundy money

    Age
    11 to 14
    Challenge level
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    How much money did the Queen give away in pence as a power of 2?
  • Negative Power
    problem

    Negative power

    Age
    14 to 16
    Challenge level
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    What does this number mean ? Which order of 1, 2, 3 and 4 makes the highest value ? Which makes the lowest ?
  • Tens
    problem

    Tens

    Age
    16 to 18
    Challenge level
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    When is $7^n + 3^n$ a multiple of 10? Can you prove the result by two different methods?
  • Elevens
    problem

    Elevens

    Age
    16 to 18
    Challenge level
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    Add powers of 3 and powers of 7 and get multiples of 11.
  • Largest Expression
    problem

    Largest expression

    Age
    14 to 16
    Challenge level
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    Which of these five algebraic expressions is largest, given $x$ is between 0 and 1?
  • Powerful Zeros
    problem

    Powerful zeros

    Age
    14 to 16
    Challenge level
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    How many zeros are there at the end of $3^4 \times 4^5 \times 5^6$?
  • Perfectly Square
    problem

    Perfectly square

    Age
    14 to 16
    Challenge level
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    The sums of the squares of three related numbers is also a perfect square - can you explain why?
  • The Public Key
    problem

    The public key

    Age
    16 to 18
    Challenge level
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    Find 180 to the power 59 (mod 391) to crack the code. To find the secret number with a calculator we work with small numbers like 59 and 391 but very big numbers are used in the real world for this.