Did you check Number Formatting
documentation? I think it might help you.
is for currency and depends on the culture (your language and country).
is the format where 0 is space for a digit while "." might be decimals separator or the group separator.
If your culture is en-EN and you are displaying 1.234, your number will be one unit and two hundred thirty four thousands of unit BUT if your culture is de-DE, you are representing one thousand two hundred and thirty four units and the number is displayer with 3 decimals.
The first 0 is, afaik, the argument number (always 0).