> 
> This should handle periods or commas as the separator.
> 
> a = "24,4 + 55,2 + 55 - 44,0"
>    => "24,4 + 55,2 + 55 - 44,0"
> a.scan /(\d+,?.?\d*)(?=\s|$)/
>    => [["24,4"], ["55,2"], ["55"], ["44,0"]]
> 

Some problems here:
- signs are disregarded ("-24,4" becomes "24,4")
- Invalid numbers are accepted: eg. "24,.4" "24,." "24." "24,"
- "." should be escaped. As you used it here, it means "any character"
(except newline), so many invalid numbers are accepted (e.g. "24w"...)
- If something different from whitespace follows the number, it is not
or false accepted, e.g. "24.4." becomes "4." instead of "24.4"
- ...


Alexis.