So it will hold if we put a=-1, b=1 and c=-1 right? let’s do it! I even came up with a ‘proof’ (I am an ex-physicist so I apologise if this is considered to be far from rigorous) as follows.įrom the distributive law of multiplication we have I asked on Twitter, I asked in my office, I asked some math teachers I know. I have to admit that I couldn’t come up with an answer that satisfied my non-mathematical friend which bugged me no end so I asked around….’How would you explain it?’.
One such question that came up while on a night out was ‘why is a minus times a minus equal to a plus?’ Among my friends I am the resident mathematics nerd and so I get asked all sorts of weird and wonderful little questions ranging from the trivial to the impossible to answer.
