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Secondary live problems and recent solutions

Each time you visit the NRICH site there will be some activities which are 'live'. This means we are inviting students to send us solutions, and we will publish a selection of them, along with each student's name and their school, a few weeks later. If you'd like to know more about what we're looking for, read this short article.

The last day for submitting solutions to these live problems is Monday 9 June.

Live problems

No live problems at the moment

Recently solved problems

  • Which is bigger?
    problem
    Favourite

    Which is bigger?

    Age
    14 to 16
    Challenge level
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    Which is bigger, n+10 or 2n+3? Can you find a good method of answering similar questions?

  • Sealed Solution
    problem
    Favourite

    Sealed solution

    Age
    7 to 14
    Challenge level
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    Ten cards are put into five envelopes so that there are two cards in each envelope. The sum of the numbers inside it is written on each envelope. What numbers could be inside the envelopes?

  • Climbing Complexity
    problem
    Favourite

    Climbing complexity

    Age
    11 to 14
    Challenge level
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    In the 2020 Olympic Games, sport climbing was introduced for the first time, and something very interesting happened with the scoring system. Can you find out what was interesting about it?

  • Charlie's delightful machine
    problem
    Favourite

    Charlie's delightful machine

    Age
    11 to 16
    Challenge level
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    Here is a machine with four coloured lights. Can you develop a strategy to work out the rules controlling each light?

  • Shifting Times Tables
    problem
    Favourite

    Shifting times tables

    Age
    11 to 14
    Challenge level
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    Can you find a way to identify times tables after they have been shifted up or down?

  • Keep it simple
    problem
    Favourite

    Keep it simple

    Age
    11 to 14
    Challenge level
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    Can all unit fractions be written as the sum of two unit fractions?

  • Finding factors
    problem
    Favourite

    Finding factors

    Age
    14 to 16
    Challenge level
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    Can you find the hidden factors which multiply together to produce each quadratic expression?