On Dec 1, 2012, at 10:25 AM, Joe Niederberger <niederberger@comcast.net> wrote:

So, Clyde, can you briefly sketch your approach to introducing negative numbers and their rules, esp. the infamous one? Any key points?

What do you mean by "introducing"? You mean like your friend telling you how to play the violin? Or attending a briefing? Where is the achievement in that? Shouldn't the task be to teach, not introduce?

Bob Hansen