I recently went through that time of the year again, where students were desperately trying to figure out their grades to within a hair's breadth, and trying to make deals with the devil (me) to pass (or get whatever grade is needed to counteract how they are doing in all their other classes). I posted all the grades for the last test in my classes to help people who are trying to decide whether to use a late drop. (Students could drop a small number of classes in their careers near the end of the semester.) I also got all the calls and e-mails from students desperate to pass, frequently sure, just positive, that they could not have done so badly on the last test. The machine must have made a mistake with their opscan. I also always get the (slightly) more subtle students asking hopefully if there will be a curve. (By which they mean, "Will you add some points to the tests so my score is better?")
But I usually get one other type of question near the end of the semester, usually in my lower level class: "How do I figure out my grade?" Or frequently just: "I keep trying to figure out what my grade is, but I don't understand how to do it." Granted, I have a moderately involved grading system which involves several categories, such as labs, homework, quizzes, and class participation as well as three tests and a final, but ultimately these just boil down to following the instructions to calculate each component of the grade and adding these up.
A few years back I just gave up and gave my students an Excel spreadsheet into which they can enter their grades to find their final grade. But I think about it every semester, and it occurs to me that if students are having trouble figuring out their final grade, they are having trouble with fairly basic math (averaging and percentages, mostly), and that this does not bode well for their grade in a math class. It comes back to what a friend of mine told me years ago: students who are failing math classes frequently don't know it, because they're bad at math, so they can't correctly figure out their grade.
(As an aside, they are usually disappointed to discover that it will not tell them their grade without knowing the final exam grade, which is worth 20 points of the final grade. They often want to know "But what's my grade without the final?", which I don't understand at all. Without the final, the highest grade they can get is an 80. If you want to estimate your grade, you have to input some estimate for the final, because the final contributes to the grade. It's that simple. I can't calculate your grade without the final, because the final is a part of it. I usually recommend students use their test average to estimate their final exam grade, but it is an estimate. Anything you do to figure your grade "without the final" involves in some way estimating the final, but students don't seem to get that.)