Hello, I am trying to just multiply Roll Ft Size x Lin Ft. But I keep getting an error. What am I doing wrong here?Thank you for any help here.  

I am looking at a way to deplete inventory of items when adding a kit to inventory. For example:I have 1 kit that contains 2 A's 4 B's, and 1 C. SO when I add a kit to my inventory, it removes 2 A's, 4 B's, and 1 C. How would I make this work? Thank ...