Let me start by saying I did search on google and inside the forum here for an answer to my question, but with no luck yet. So I was hoping someone could explain it to me or maybe send me a link to a post already answering this.

This is for an inventory tracking spreadsheet. What I need to do is be able to add a formula in the background that will automatically adjust the cells in that formula, while still being able to edit those cells manually. For example.. (hope I use the code button right haha)

   1            2            3
Item A    
Item B
Item C

Kit A        Kit B       Kit C
^Just a basic version of my spreadsheet

What I need to have the amounts of the kits adjust the amounts of the items, while still being able to manually enter the amount of each item. So lets say I have 10 each for items a thru c. When I make kit a, it requires item a and item b in it. So if I enter 1 for kit a, I need to to adjust items a and b to have 9 each now. Make sense so far?

With that being done, let's say I receive a shipment of item a, now I need to add 10 more to it, making the total 19. So I want to be able to change the data from 9 to 19 without effecting the formula I put in for the kits.

I hope that makes sense to everyone, tried to be as detailed with it as possible. I'm still fairly new to using excel with my new job so I hope this isn't something really easy to do that I simply just missed haha

Thanks in advance!