Is there a way to make a cell obtain a formula that will update a number each
time you open the worksheet? For example I created my own invoice and I want
to start my invoices at 1000 and then each time I open it to create a new one
that number would automatically update one so it would be 1001 . . . . 1002 .
.. . . 1003 etc. etc. I've looked and looked and can't figure out how to do
it and I'm sure it's possible. Please help!