Basically someone I know had a problem to solve. One of the rates involved was 80 units/1 mL. I solved by starting from what it stated which was 80 units/1mL, she solved it by saying 80 units = 1mL. These are both legitimate statements that lead to the same answer.

My problem is how do we get from one to the other and basically what I've found out is that all rates are equal to a unit less number 1 so that they cancel. Can someone explain Intuitively why this is? I guess it's because in order to relate thing to each other there has to be some placeholder that doesn't relate to the two so they can differentiate in that statement.