Question

How did you get 16 after adding 20 from both sides? when I do -8 plus 20, I get 12, not 16?

Answer 1

So if there were -4+20 the answer would be 16. When you add things, it goes to the right of the number line. When you subtract stuff it goes to the left. Simple but there are more rules like when this happens: 6--4 the two minuses turn into a plus 6+4—and other stuff. So -8 you have 8 negative signs and 20 positive signs. When a positive and a negative are added together they cancel each other out so now you have 12. This is modeled on the attachment. Hope this helped!

Explanation: