You can use filter or appropriate method (since I dont know what exactly you want to alter) and use string replace function
str_replace()
Probably I think that it is issue below. http://stackoverflow.com/questions/437371/php-locale-aware-number-format
Because Q2A don't appoint parameter of number_format() definitely, result may depend on locale. I do not have the experience corresponding to this matter, can you cope at qa-base.php (arround L112)?
Example:
I'm sorry if worthless.
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