|Did you try my suggestion?|
I used exactly what I suggested in my previous response and got these results:
You should review the Excel Help files for VLOOKUP so you understand how it works.
VLOOKUP(lookup_value, table_array, col_index_num, range_lookup)
=VLOOKUP( C1, $A$1:$B$9, 2, 1)
A B C D
1 0 E2 19.5 A1
2 4.1 E1 12.3 B2
3 6.5 D 18.09 A2
4 8.1 C2 3.9 E2
5 10.1 C1
6 12.1 B2
7 14.1 B1
8 16.1 A2
9 18.1 A1
The VLOOKUP formula will "look up" the numerical grade (lookup_value) in first column of the table (table_array) and return corresponding letter grade from the second column(col_index_num). The range_lookup argument is set to TRUE (1), so it will return the letter grade that corresponds to the highest number that is less the lookup_value.
You can put the table anywhere you want, just change the $A$1:$B$9 to match the range where you put the table.
The lookup_value range I used was C1, but you should use the cell references for the cells that contain your numerical grades. Do not use the dollar signs with the lookup_value range so you can drag the formula anywhere you want, as I did in the example above.
Note: If you are using any version of Excel beyond 2003, you can use more than 7 conditions in an IF statement, but that is very cumbersome.