Read all about the number pi and the mathematicians who have tried to find out its value as accurately as possible.
This article for pupils gives some examples of how circles have featured in people's lives for centuries.
Can you reproduce the Yin Yang symbol using a pair of compasses?
What shaped overlaps can you make with two same-sized circles?
What shapes are 'left over'?
What shapes can you make when the circles are different sizes?
What happens when you use more than two circles?
Using circles cut from tissue paper will make the overlap easy to see.
They also look good displayed on the window against the light because the overlap comes out a different colour.
Asking pupils to move the circles over one another gradually will help them to see the possibilities clearly.
As names of shapes are not required, this activity provides a chance to encourage careful description using appropriate language.
This is a good opportunity to talk about the symmetry of circles too.