What I've seen generally is that teachers and homework teach how to do something, then reinforce that through endless dull repetition, instead of teaching the '

What I've seen generally is that teachers and homework teach how to do something, then reinforce that through endless dull repetition, instead of teaching the 'why', which would massively reduce the amount of reinforcement needed. I gues the issue is that a lot of the time the teacher doesn't properly understand the subject.