A Long Time at the Till
Age 14 to 18 Challenge Level:
Try to solve this very difficult problem and then study our two suggested solutions. How would you use your knowledge to try to solve variants on the original problem?
Stage 5 Cipher Challenge
Age 16 to 18 Challenge Level:
Can you crack these very difficult challenge ciphers? How might you systematise the cracking of unknown ciphers?
Sorted
Age 14 to 18 Challenge Level:
How can you quickly sort a suit of cards in order from Ace to King?
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NRICH is part of the family of activities in the Millennium Mathematics Project.
NRICH is part of the family of activities in the Millennium Mathematics Project.