Excell 2000
I read your comments ad I would like to precise my needs. I tried to format
the cell like you told me to do < -h:mm and when I type 8:00 the
result gives -8:00 but no further calculation can be made such as :

Let say -8:00 in A1 and 2:00 in cell A2 and formula A1-A2 in A3 should give
me -10:00 as a result in A3.

Any others ideas ??

Thanks!

André Lavoie