> E.g. 6 Students walk into an empty classroom, 10 walk out, you have -4 Students left. The only trouble here is in the assigned interpretation. You do have -4

> E.g. 6 Students walk into an empty classroom, 10 walk out, you have -4 Students left. The only trouble here is in the assigned interpretation. You do have -4 students left compared to the initial state but there is no reason to assume the initial state was 0.