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.

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

I added together some of my neighbours' house numbers. Can you explain the patterns I noticed?

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.