Sounds like text instead of numbers.

See if this returns a result

=SUMPRODUCT(--(A1:A20))

If so, it is text, and should be corrected.

--
HTH

Bob

(there's no email, no snail mail, but somewhere should be gmail in my addy)

"Jo" wrote in message
...
"Sum" function is returning a zero value for a list of positive numbers.
Another function I tried to enter showed the formula in the cell instead
of
the result. (I have checked that "automatic" is selected in tools,
calculations.)