I need a basic formula as soon as possible! I know that I have done this type
of work before however, it has been so long since that I cannot remember how
to do it.

I have a spreadsheet with various items named on it, and the amount we have
next to it. What is the formula that I need to put in, in order to keep track
of what we have i.e. when something gets taken out of the archive, I can just
type it in and see straight away what is left?

I HOPE THIS MAKES SENSE!

many thanks.