TITLE: How to avoid stupid mistakes in calculus exams without checking the whole process?
QUESTION [17 upvotes]: Few days ago I failed my Calculus exams. And again it was mostly due to simple mistakes such as forgetting about minus in front of fraction, switching y coordinates of two points etc.
The assignments are pretty simple, for example calculating area defined by N curves or analyzing a function. But we have only ten minutes for each, so there is almost no time left to check the results.
My question is: How to avoid such mistakes without checking everything?

REPLY [9 votes]: Always show enough work on your exam so that it is clear, when you make an error, what sort of error it is. 
Writing clearly makes it easier to grade, but it also makes it easier for you to check later.
At heart, if you are making a lot of stupid mistakes, either (1) you don't really understand the steps, and are just applying rote thinking, or (2) you might have attention issues.
Things you can do to improve attention: eat healthier, exercise, and sleep better. Quite a lot of people self-medicate with caffeine. As a last resort, consider coaching and/or prescription medications. But treating ADD is quite a ways outside this group.