"Nevermind" writes:
What have you done about this? Let some bad grades happen and
hopefully motivate the child to be more careful? Offer rewards for
homework done right the first time? But even if we used that approach,
I'd worry that in school, where the only reward comes later in the
form of good grades, he would still rush through work and be careless.

Arrgh. "Good grades" are not the reward for doing schoolwork. The
satisfaction of getting the right answer is the reward. Enjoying the
mental challenge is the reward. Learning something is the reward. Even
the approval of your parents and peers (if you have the right peers) can
be the reward.

I don't think you can really be successful in school unless you have
many much more important reasons to do schoolwork, than grades.

David desJardins