Why is negative times negative positive? (VIDEO!)
In grade five I asked my mathematics teacher “Why is negative times negative positive?” The reponse I received was unenlightening to say the least: “It just is!” This made me angry.
In this short video I explain, once and for all, why this peculiar fact is so. [Actually ... that is not quite true! I explain it twice! The first is a way that is acceptable to most, student and teacher alike, and the second is a way that digs a little deeper into the mathematics "behind the scenes" of the first approach, one that satisfies the true mathematician within each of us!]
This video has been split into PART I and PART II: