Date: Nov 28, 2012 6:49 AM Author: Peter Duveen Subject: Re: Some important demonstrations on negative numbers I'm in Chandy's camp on this one. Mathematics takes common sense notions of number and expands upon them. That is why I have often attempted to find a common sense premise, which I often called "self-evident," such as that the area of a rectangle is proportional to the length of its side, the other side remaining constant, to demonstrate other properties, such as the l x w formula. If we loose sight of the common-sense foundations of our subject, we breed the confusion that is oft associated with the study of mathematics.