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game

Celebrate 25 years of NRICH

5 to 14

To celebrate NRICH's 25th birthday, why not play this special version of our classic game, Got It? Can you devise a strategy so that you will always win?

game

Patience

11 to 14

A simple game of patience which often comes out. Can you explain why?

game

Pass the peas, please

5 to 7

A game for 2 or more players. Practise your addition and subtraction with the aid of a game board and some dried peas!

problem

3388

11 to 14

Using some or all of the operations of addition, subtraction, multiplication and division and using the digits 3, 3, 8 and 8 each once and only once make an expression equal to 24.

problem

Little and large

16 to 18

A point moves around inside a rectangle. What are the least and the greatest values of the sum of the squares of the distances from the vertices?

problem

Diverging

16 to 18

Show that for natural numbers x and y if x/y > 1 then x/y>(x+1)/(y+1}>1. Hence prove that the product for i=1 to n of [(2i)/(2i-1)] tends to infinity as n tends to infinity.

problem

Code breaker

7 to 11

This problem is based on a code using two different prime numbers less than 10. You'll need to multiply them together and shift the alphabet forwards by the result. Can you decipher the code?