Didn't take great notes in class? Missed a day and need to get the general idea? Crash course has information on lots of topics. Find the right subject then find the topic to get the jist of what you missed.
Khan Academy has lessons and tutorials to teach you key concepts you might not have understood the first time.
Create quizzes and flash cards to use and share with your study group or go solo and leave your friends in the dust.
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