Now let's see what adding and subtracting negative numbers looks like: Rule, Example. plus, Two like signs become a positive sign, +(+), 3+(+2) = 3 + 2 = 5. There are also rules for calculating with negative numbers. In order to and use the rules for adding, subtracting, multiplying and dividing them. 2. Order of. If you are talking about multiplication and division of signed numbers the rules are. Positive x Positive = Positive Positive x Negative = Negative.