Have you seen this way of doing multiplication ?

What is the largest number which, when divided into 1905, 2587, 3951, 7020 and 8725 in turn, leaves the same remainder each time?

How good are you at finding the formula for a number pattern ?

Investigate matrix models for complex numbers and quaternions.

Find out how the quaternion function G(v) = qvq^-1 gives a simple algebraic method for working with rotations in 3-space.

See how 4 dimensional quaternions involve vectors in 3-space and how the quaternion function F(v) = nvn gives a simple algebraic method of working with reflections in planes in 3-space.

Simon and Trevor used the Newton Raphson method to solve this, Trevor using a spreadsheet and Simon a program in C. Andrei used interval halving and a graphical solution.

This article gives a proof of the uncountability of the Cantor set.

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.