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Nobody has ever made reviewing with flashcards as personalized as Brainscape. Brainscape's innovative "smart" flashcards work in timed intervals that a user rates on a scale of 1 to 5. Brainscape then uses an adaptive learning algorithm to differentiate instruction and display the flashcards the user needs to practice. This is a great way to learn difficult subjects and break down difficult concepts. An added bonus is the user can crowdsource flashcards to find pre-made cards or make his or her own. Perhaps digital reviewing may work well for your class.