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Penta Colour

In how many different ways can I colour the five edges of a pentagon red, blue and green so that no two adjacent edges are the same colour?

Eight Dominoes

Using the 8 dominoes make a square where each of the columns and rows adds up to 8

Snowman

All the words in the Snowman language consist of exactly seven letters formed from the letters {s, no, wm, an). How many words are there in the Snowman language?

Twin Line-swapping Sudoku

Age 14 to 16
Challenge Level
Twin A solutionTwin B solution
The NRICH Project aims to enrich the mathematical experiences of all learners. To support this aim, members of the NRICH team work in a wide range of capacities, including providing professional development for teachers wishing to embed rich mathematical tasks into everyday classroom practice.
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