I teach high school math. I sell a product to a market that doesn't want it, but is forced by law to buy it.
Dan MeyerThe physical five oranges goes up the ladder to the picture of the five oranges which goes up to the representation of the five oranges as a numeral. This points in the direction of a definition of abstraction: when we abstract we voluntarily ignore details of a context, so that we can accomplish a goal.
Dan Meyer