random number in a cell

[just4fun]

I am trying to find a way to generate a random number (used for an invoice
number) in a certain cell, each time a the workbook is opened. So far I have
only been able to generate a random number each time anything is input into
the spreadsheet. Any suggestions??

 

[T. Valko]

See this:

http://www.mcgimpsey.com/excel/udfs/sequentialnums.html