Went to a one-room school. There were about a dozen kids, grades one through eight. Not lots of kids, but still pretty challenging for a teacher. Sometimes us students tried to help. As a second grader, I remember trying to coach an older kid who was having trouble with fractions. "Invert and multiply, Larry! ", my classmate and I would whisper, “but why? why?” he would whisper back. New math students could probably answer that one right away.