What I find offensive is the fact that some teachers refrain from posting your last few quizzes so that you don't know your quarter grade, and therefore can't do the math.
Carly -- You make a lot of good points. Do you think teachers do this on purpose? I can't speak for everyone, but in my case, I'm just slow. I'd be thrilled if everything was graded, but it's not. The grade chart helps people guess and plan more strategically, but grades are not actually due from teachers until 4:00 p.m. on the Monday after finals end.
Is it reasonable to expect teachers to have quarter grades finished more than a week before that deadline so that students can decide whether or not to study for their final exams?