Equation to populate new number
Hello. I have a sheet with 4 columns: one is the name of the material (Material Name), the next is the quantity of that material that we have in stock (Quantity), the next one is who claimed this material (Claimed By), and then the last column is how much quantity that person claimed (Quantity Claimed). So for example, if we have 1000 feet of wire left over, someone can go and claim 500 feet of it.
I am looking for an equation or formula or just a way so that when someone puts a number in the "Quantity Claimed" column, it automatically subtracts that number from the "Quantity" column so the number in the "Quantity" is updated. Seems easy enough but I can't figure it out.