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<p>A lot of times, problem sets cover mechanics and calculation, whereas exams cover understanding of the concepts. (I’m not defending this, merely reporting it-- better problem sets would have easy problems to practice the mechanics and hard problems to exercise the concepts.) Then when the test comes, some students find that they how to do the calculations, but don’t know how to apply them.</p>
<p>For the student, the answer is more practice in addition to the assigned problem sets. The student needs to figure out what the professor will actually expect students to be able to do on the exam. Looking at previous exams from prior years is one great idea; going to office hours and asking the professor point-blank what the important concepts are is another.</p>