(I will do my best to entirely explain the subject) To understand Positives and Negatives you need to have a number line.
<u>-3 -2 -1 0 1 2 3</u>
Your whole life you have been using positives and negatives when you subtract or add a number. 9 - 2 is really just 9 + -2
With the number line it should be easier to understand that for every single time you add or take away you change the value. The more you take away (Negative numbers, 5 + -6) the farther down the value goes to the left, more towards the negative side (5 + -6 = -1). The same goes for addition (-6 + 9 = 3).
To multiply all you need to do is count how many times you see a negative number. If you see an even number of negatives then the answer will be positive because on the number line you went from one side to the other multiple times, left right left right and all that jazz. Hopefully i made this make more sense to you, if there is anything i need to clarify on please make it known so i can edit my answer.
