I've been told by a fellow co-worker that the IF formula that I'm wanting
cannot be done. Please let me know if it can be done.

I'm needing to take a spreadsheet that is used for inventory to calculate
each product that is "spoken for" to be deducted from the total of the
inventory BUT after the new inventory totals are given, to add the inventory
back into this number if it was not delivered.

Can this be done? In my mind, yes...but I'm not sure how to do this one.
I'm a beginner "IF Formula" creator.

Thanks.