I want to calculate a letter grades based on marks. The letter grades
are divided up into a group of 10.

F 0 to 49
D 50 to 54
C- 55 to 59
C 60 to 63
C+ 64 to 67
B- 68 to 71
B 72 to 75
B+ 76 to 79
A- 80 to 84
A 85 to 90
A+ 90 to 100

"IF" only allows 7 functions. How can I get around this restriciton?
I'm somewhat of a novice when it comes to formula's so a bit of an
example would be a great help.

Thanks Rick