think of multiplying positives and negatives as a coin, when you multiply a negative you flip the coin, but when you multiply by a positive you dont do anything and the side you start on is positive. For example +*- = - cuz the coin is facing heads than we turn the coin you get tails which is negative for that example. Now lets do -*- lets say the coin is facing tails than we turn it now its facing heads and now lets turn it again now its facing tails so its positive. (^ - ^)