Assuming that multiplication is only (!) repeated addition and that
division is only repeated subtraction, the customary rule--as we all
know--is merely a short-cut way of expressing what is really done when
computing with paper and pencil.
If I may add another query relevant to OoO and with due apologies to
colleagues who do not use the American-English idiom in their teaching:
who was the first to coin the expression MY DEAR AUNT SALLY as a
remembering aid for the OoO?
Thanx!
Barnabas Hughes