Hi everyone, my name is Dreak, Im working on my shops inventory lists. I've got most of the data in the spreadsheet already but Im stuck on a problem that seems quite simple in theory but not easy to do.

I have a "on hand" column and a "total" column which need to remain equal. Then i have a "quantity used" column. This column is were i would like to input an about and have it effect the "on hand" amount. I know using the sum function i can get this to happen. But i want the values imputed into the "quantity used" column to effect the totals and then reset to 0 to '0' so i can put new input. Help?