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Academic grading in the United States commonly takes on the form of five, six or seven letter grades. Traditionally, the grades are A+, A, A−; B+, B, B−; C+, C, C−; D+, D, D−; F; with A+ being the highest and F being lowest. Numeric to letter grade conversions generally vary from system to system and between disciplines and status. In some cases, grades can also be numerical. en.wikipedia.org