How many differently shaped rectangles can you build using these equilateral and isosceles triangles? Can you make a square?

This article for pupils and teachers looks at a number that even the great mathematician, Pythagoras, found terrifying.

Read all about Pythagoras' mathematical discoveries in this article written for students.

An introduction to proof by contradiction, a powerful method of mathematical proof.

If the yellow equilateral triangle is taken as the unit for area, what size is the hole ?

Ranging from kindergarten mathematics to the fringe of research this informal article paints the big picture of number in a non technical way suitable for primary teachers and older students.

Using the interactivity, can you make a regular hexagon from yellow triangles the same size as a regular hexagon made from green triangles ?

What fractions can you find between the square roots of 65 and 67?

The number 2.525252525252.... can be written as a fraction. What is the sum of the denominator and numerator?