I teach mathematics at a university, and we have an on-line homework system for entry-level, single-variable calculus. (How well this really works overall is a

I teach mathematics at a university, and we have an on-line homework system for entry-level, single-variable calculus. (How well this really works overall is a discussion for another time). One thing that the system lets me do is see their incorrect solutions (for each problem they usually get a few tries). For a subject like calc 1 or 2, it is usually very easy to spot the error w/o even seeing the intermediate steps, and to give them useful hints. But I'm not plugged into email all the time, so this only works for students who start early enough. I tell the class this on the first day, and repeat. And it still surprises me how many students who can benefit from more feedback nevertheless start last minute. Some have legitimate reasons, sometimes: upcoming deadlines, juggling work schedule, other classes that demand more attention. Still, suprrisingly few students seek feedback or start early enough to benefit from it, even if they aren't getting the grade they want.