Description: In this video, we think about what |a-b| really means, and we verify that |a-b| = |b-a| by looking at an example. So let me draw a little quick number line right over here. The way I've drawn it, b is to the right of a on our number line, and by our convention, b is going to be greater than a. Well I could just take the larger of these two numbers, which is going to be b, and then subtract out the smaller.*Teacher Advisor is 100% free.