FIFO Inventory

FIFO.xlsHi Guys,
I have been looking over this forum for an answer to this and I am stumped. Attached I have a sheet containing three tables; Bought, Sold, and Remaining Inventory. Each table has a column for five products; Eggs, Bread, Milk, Apples, and Yogurt. The first column of each table has a Purchase Order # (PO#) in it. I would like to be able to subtract the Sold from the Bought for Oldest to Newest PO# and put the remainder into the remaining inventory table. Once a PO# is at zero I would like to darken the cell to "Grey". Thank you in advance for the help.



FIFO.xls