Usually, A+ is 95+ or 10, A or A- or B+ may then be considered a 85+ or 9; B, B-, or C+ may be considered 75+, and therefor a 7, and so on. F is 50 +, and E(in my system, according to Glaive, it could be a "U" as well), is anything < 50 (5), for if you're below 50, you're not going to pass anyways, and therefor not point splitting hairs.