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? ...

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

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

This package is designed around work on percentages which is outlined in the KS3 Mathematics Framework. One NRICH game and one problem have been identified to support the work on percentages in each. . . .

A group of interactive resources to support work on percentages Key Stage 4.

Problem one was solved by 70% of the pupils. Problem 2 was solved by 60% of them. Every pupil solved at least one of the problems. Nine pupils solved both problems. How many pupils took the exam?

A political commentator summed up an election result. Given that there were just four candidates and that the figures quoted were exact find the number of votes polled for each candidate.

An activity based on the game 'Pelmanism'. Set your own level of challenge and beat your own previous best score.