The letter-based system used today in many primary, secondary, and post-secondary schools was first used at Mount Holyoke College in 1897, with the exception that it used an E rather than F. Despite Mount Holyoke having the first complete A-E system, Harvard allegedly handed out a B grade in 1883. The letter-based grading scale at Mount Holyoke worked by assigning each letter a numerical range (e.g. A being 90-100), with E representing failure. Eventually, as the A-E grading scale became more popular, the E was dropped and replaced by an F because the letter F more logically denotes failure. The other letters in the system, A, B, C, and D, represent the four possible passing grades.