I have a formula that is already matching my score to my GPA, this is being
pulled from the formula below:

formula is: =SUMPRODUCT(--($AR$2:$AR$37=D3),$AS$2:$AS$37)

lookup table sample is:
Score.........GPA........Grade..
100.......|.....4.......|.....A......
95.........|.....3.5....|.....A-....
90.........|......3......|......B....

NOW: I need the above formula to refer to the letter grade (A), (B), (C), etc.