If you multiply unlike signs, the product will be negative.
if you add unlike signs, oh. you can't add a numbers that has unlike signs. In this case, you will subract it. And the answer is either negative or positive. it depends on who has the higher value. for example, +10 - 9 is equals to +1. because positive ten is much higher that negative nine. But if this the equation +9 --10 the answer will be -1. same as subtrating unlike signa