Incidentally, this is now explicitly taught in elementary school math classes. They call it 'number bonds' and it often drives parents crazy because "OMG IT ISN

Incidentally, this is now explicitly taught in elementary school math classes. They call it 'number bonds' and it often drives parents crazy because "OMG IT ISN'T HOW I LEARNED IT!", but it is clearly a better strategy than 'just memorize this multiplication table'