I would still insist on that a kid can manage with his/her homework even if little had been explained in class by the teacher. A teacher might by pathetic and useless - fine, but there are books and good books and loads of them for general stuff (e.g. basic maths). And a kid, seeing that his/her teacher is strongly underperforming in class, should find other ways of achieving the necessary level.
I'm a bit lazy at times. And I didn't go to school half of the time. And I don't go to University third of the time. Still, I find in myself enough patience to take a book, read it, do exercises. And at the day of the exam I score highest among hundreds with flawless class assistance record, without going a single time to the class in a whole year. And I assure you that studying here is no easy deal.
So, please, do not tell me that some elemental school homework cannot be accomplished by a kid alone. If he wants to do it, he'll succeed, if he doesn't he will fail sooner or later in the life, or the life itself will make him change the attitude.
(P.S. I'm not implying that I didn't go to school, don't go to University and yet perform at high level on the exams, I'm not that smart. <img src="/images/graemlins/laugh.gif" alt="" /> There have been a few cases of success with such attitude, but that's not the normal thing. The point is that nor school, nor University are the only and ultimate sources of knowledge and that if you don't learn something in there, you can't learn it anywhere else.)