Look, most people don't consciously use algebra at all! When they do intentionally use algebra I would be very surprised indeed if they did use something else t

Look, most people don't consciously use algebra at all! When they do intentionally use algebra I would be very surprised indeed if they did use something else than the standard field of real numbers. I honestly have no idea what meaning you put into the word "algebra"; on reflection it's pretty weird to bring it to a discussion of percentages and their interpretation. In the same vein, what do you wish to prove by bringing up the example of the nurse and the doctor? They seem to do the sensible thing and communicate in absolute quantities rather than rations. Still patients do die to mistakes in the drug administration every now and then, and often from the rather banal mistake of missing a decimal point.