Calculate grades with VLOOKUP

Generic formula 

=VLOOKUP(score,key,2,TRUE)

Explanation 

To assign a grade based on a score, you can use the VLOOKUP function configured to perform an approximate match. In the example shown, "key" is the named range B5:C9, the formula in F5. copied down, is:

=VLOOKUP(E5,key,2,TRUE)

where "key" is the named range B5:C9.

Note: the lookup table must be sorted in ascending order, and VLOOKUP must be set to approximate match mode.