Thanks Bob. This worked, but wasn't the result I was after. Appreciate your
help.
Regards
--
Carla


"Bob I" wrote:

Open a new sheet with 1904 "Unselected".

Plug 1:00 in A1
4:00 in B1
=A1-B1 into C1

Observe ##### is displayed

Now set 1904 in options

C1 should now show -3:00

Carla wrote:

Hi David,
I have played around with the 1904 date system, the cell formatting used,
and the subtraction formula, but am not having much luck. Can you please
assist further if I provide the document I am working on?
Thanks