when you are adding two negative numbers, the sum is basically the two numbers added together but as a negative. when added together they create a larger negative number; ex. -2 -8 = -10 which is the same as 2 + -8 = -10. when you are multiplying two negative numbers, you are really just multiplying the numbers and they come out to be a positive. a negative times a negative is a positive. ex. -5 x -5 = 25.