SUM(C:C) always returns 0

[Reepicheep]

in the function pallette window, it returns the right value.
(it was the one to give me the function, from pointing and clicking on the
whole column)...
but in the spreadsheet, it always equals 0....
why?

 

[Max]

Assuming col C does contain some "numbers"

try some diagnostics:

a) Maybe calculation is in "manual" mode ?

Press F9. Does it calculate ?

To check / change the calculation mode:
Click Tools > Options > Calculation tab > Check "Automatic" > OK

The calculation mode is set by the first excel book
opened in the Excel session.

If the first book opened has "manual" setting for calculation mode,
all subsequent books opened during the same Excel session will
be at "manual" calc, irrespective of their own saved calc mode.

b) The "numbers" in col C may be text

Put in say, D1: =IF(ISNUMBER(VALUE(C1)),VALUE(C1),"")
Copy D1 down col D

Now try in say, E1: =SUM(D)