An introduction to proof by contradiction, a powerful method of mathematical proof.
This article for pupils and teachers looks at a number that even the great mathematician, Pythagoras, found terrifying.
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.
Tim Rowland introduces irrational numbers
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?
How many differently shaped rectangles can you build using these equilateral and isosceles triangles? Can you make a square?
Read all about Pythagoras' mathematical discoveries in this article written for students.
If the yellow equilateral triangle is taken as the unit for area, what size is the hole ?
Can you express every recurring decimal as a fraction?