Despite formula I use (for example SUM) result is always zero.

[Anida]

Despite formula I use (for example the most simple SUM) it always shows me
zero result even it should show a lot more. Values in other cells (cells that
I sum) are in number format. Why this happens??

 

[Max]

This quick fix might suffice for you
Instead of using: =SUM(A2:A5)
use this, array-enter it, ie press CTRL+SHIFT+ENTER to confirm the formula:
=SUM(A2:A5+0)
The "+0" will coerce all text numbers (if any) within the source range
(A2:A5) to real numbers w/o impacting their intrinsic values, and return the
desired results. Happy? hit the YES below

 

[Anida]

When I put =isnumber(a2) it shows me true, and for =istext false. What next?

 

[Dave Peterson]

Make sure that calculation is set to automatic.

In xl2003 menus:
tools|options|calculation tab

And your range to sum does include A2, right?

 

[Dave Peterson]

And any chance that the sum is 0? Maybe you have positive, negative and zero
values in the range?

And one more thing to check.

Type these two formulas in separate cells:
=count(A1:a10)
=counta(a1:a10)

(change A1:A10 to the range you're summing.)

=count() will count the numbers in the range.
=counta() will count numbers, strings, even formulas that evaluate to "" in the
range.