Note we add the minus numbers,we add the plus numbers then tidy it up. Rule 3: Multiplication and signs: The basic rules for multiplication and signs are as. The game comes with Rules, 4 playing boards, 4 sets of 4 playing tokens, Plus and Minus was published in the s or s, by the same publisher as. A listing of positive and negative rules for adding and subtracting integers. We usually don't say "positive" or write the + sign so you will not see two plus signs.