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 28 April.
Live problems
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problemClimbing 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?
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problemCharlie'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?
Recently solved problems
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problemKeep it simple
Age11 to 14Challenge level
Can all unit fractions be written as the sum of two unit fractions?
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problemFinding factors
Age14 to 16Challenge level
Can you find the hidden factors which multiply together to produce each quadratic expression?
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problemShifting 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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problemCuboid challenge
Age11 to 16Challenge level
What's the largest volume of box you can make from a square of paper?
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problemTake three from five
Age11 to 16Challenge level
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?
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problemSlick summing
Age14 to 16Challenge level
Watch the video to see how Charlie works out the sum. Can you adapt his method?