I am trying to add a range if another range is "D" or subtract if the "D" is
an "R".

I have used SUMIF to add the range but cannot figure our how to not add
those with criteria of "R" and in fact subtract them with criteria of "R".

Example: =SUMIF('Inventory Sheet'!B$9:'Inventory
Sheet'!B$10000,A9,'Inventory Sheet'!$F$9:'Inventory Sheet'!$F$9999)

Any suggestions would be appreciated.