Probably the numbers looked up are text, although they look like numbers.
Use

=VALUE(YourLookupFormula)

--
Kind regards,

Niek Otten

"Martyn" <Martyn@discussions.microsoft.com> wrote in message
news:BFF92739-0A0D-4B42-B96B-38DB0E1C9D20@microsoft.com...
>I have column in which each cell is a value returned from a LOOKUP. the
> values are all numbers. A few of the cells simply have the number entered
> manually.
>
> I want to have a runnung total of the collumn at the bottom. But the SUM
> formular only adds the numbers manually entered and does not add up the
> ones
> returned by LOOKUP. How can I get it to add up all the values.