per grade grade
letter point
0-49 U 0.0
50-54 D 1.0
55-59 D+ 1.5
60-64 C 2.0
65-69 C+ 2.5
70-74 B 3.0
75-79 B+ 3.5
80-89 A 4.0/3.9
90-100 A+ 4.5/4.3