Description: Our focus here is understanding that a variable is just a symbol that can represent different values in an expression. We got this. Just watch. Created by Sal Khan. But on top of my hourly wage, I also get tips each hour. It can vary, one hour it might be lunchtime, get a lot of tips, people might get some big-ticket items. So the tips part right over here, we consider that to be a variable.*Teacher Advisor is 100% free.