To celebrate NRICH's 20th birthday, we've taken a look back in the archives and dusted off some problems from the early days, freshened them up, and added some new ideas. We hope you enjoy working on these hidden treasures!
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Favourite
Counting Factors
Is there an efficient way to work out how many factors a large number has?
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Gift of Gems
Four jewellers share their stock. Can you work out the relative values of their gems?
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Introductions to ...
This collection of articles gives introductions to important topics in mathematics
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Thinking Mathematically - Secondary students
A collection of resources aimed to help secondary students to think like mathematicians