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Circle Packing

Equal circles can be arranged so that each circle touches four or six others. What percentage of the plane is covered by circles in each packing pattern? ...

Round and Round

Prove that the shaded area of the semicircle is equal to the area of the inner circle.

Fractions and Percentages Card Game

Can you find the pairs that represent the same amount of money?

Percentage Unchanged

Age 14 to 16 Short
Challenge Level

If the base of a rectangle is increased by 10% and the area is unchanged, by what percentage (exactly) is the width decreased by ?




You can find more short problems, arranged by curriculum topic, in our short problems collection.
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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