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 the recent live problems was Monday 26 January.
Live problems
No live problems at the moment
Recently solved problems
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problemFavouriteSealed Solution
Age7 to 14Challenge level
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?
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problemFavouriteWhich Is Bigger?
Age14 to 16Challenge level
Which is bigger, n+10 or 2n+3? Can you find a good method of answering similar questions?
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problemFavouriteFinding Factors
Age14 to 16Challenge level
Can you find the hidden factors which multiply together to produce each quadratic expression?
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problemFavouriteShifting Times Tables
Age11 to 14Challenge level
Can you find a way to identify times tables after they have been shifted up or down?
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problemFavouriteMore Less Is More
Age7 to 14Challenge level
In each of these games, you will need a little bit of luck and your knowledge of place value to develop a winning strategy.
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problemFavouriteMultiple Surprises
Age11 to 16Challenge level
Sequences of multiples keep cropping up...
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problemFavouriteCharlie's Delightful Machine
Age11 to 16Challenge level
Here is a machine with four coloured lights. Can you develop a strategy to work out the rules controlling each light?
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problemFavouriteNegative Powers
Age14 to 18Challenge level
What does this number mean? Which order of 1, 2, 3 and 4 makes the highest value? Which makes the lowest?
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problemFavouriteKeep It Simple
Age11 to 14Challenge level
Can all unit fractions be written as the sum of two unit fractions?
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problemFavouriteClimbing Complexity
Age11 to 14Challenge level
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?