100 >= A >= 93 > A- >= 90;

90 > B+ >= 87 > B >= 83 > B- >= 80;

80 > C+ >= 77 > C >= 73 > C- >= 70;

70 > D+ >= 67 > D >= 63 > D- >= 60;

60 > F.

From http://www.math.utk.edu/~swise/classes/spring14/math547/

Grades