I have a formula that works for adding all quantities of a specific part number on order from "open orders" tab to the "Aircraft Inventory" tab. It populates the "Total Qty on Hand" column in the "Aircraft Inventory" tab. Formula is: =SUMIF('Open Orders'!D,'Aircraft Inventory'!A:A,'Open Orders'!B:B). What I need to add to this formula is in the "Open Orders" tab I have a quantity received column (P). I need to subtract this quantity from "Open Orders" column B (total qty ordered) to show the current qty still open in the "Aircraft Inventory" tab. I have tried a few things but I can't seem to get it to work.