Using balancing scales what is the least number of weights needed to weigh all integer masses from 1 to 1000? Placing some of the weights in the same pan as the object how many are needed?

This article for the young and old talks about the origins of our number system and the important role zero has to play in it.

Have you seen this way of doing multiplication ?

Make the twizzle twist on its spot and so work out the hidden link.

A loopy exploration of z^2+1=0 (z squared plus one) with an eye on winding numbers. Try not to get dizzy!

This article looks at how models support mathematical thinking about numbers and the number system

Introduces the idea of a twizzle to represent number and asks how one can use this representation to add and subtract geometrically.

The first part of an investigation into how to represent numbers using geometric transformations that ultimately leads us to discover numbers not on the number line.