Not able to correctly declare functions' arguments

Originally Posted by MrShorty

I believe that this is controlled in Windows Control Panel->Language and Regional settings -> List separator. Usually this is set to either , or ; Someone may have changed it to some other character. Assuming you are using Windows, check this setting and see what character is set as your systems list separator.

I checked both the system and Excel separator. System wise I have comma as a separator of decimal numbers, while in excel I'm using the dot. None of these seem to work.
I need to keep the two settings different because of some .txt files that I need to read with Excel that use the dot as a separator.

Originally Posted by xlnitwit

Hi,

Looking at the prompts you are getting it appears you use the space as a separator so it would be:
=SOMMA(33 99)

Unfortunately, this is not the case. Using space as a separator prompts the very same error.