Date arithmetic

[Dave Feustel <dfeustel verizon net>]

How is date arithmetic done in Gnumeric?
I want to put a date in a cell and have 6 
incremental dates generated in successive
cells in the row. So I need a function that
adds 1 to the date in the cell immediately to
the left. I didn't see any obvious way to do this
looking at the gnumeric date/time functions.
Is there a straightforward way to do this?

Thanks,
Dave Feustel