I agree that it was irrelevant, that's the very first thing I said. I also think it's horribly rude to correct someone's grammar so it's a good thing I didn't do that. At no point did I say "maths" was wrong, I just pointed out that it's not used here. I'm sorry you took it that way, but given that you're not the person I'm supposed to have been rude to, I'm not sure why I'm apologizing to you.
It's definitely irrelevant to call me on an alleged slight that wasn't even directed at you. Are you the forum police or something?
Differences within the same language fascinate me, I'm married to an Australian and we're both still amazed by the differences we continue to find in our supposed common language. That's why I pointed it out. Believe me when I tell you I'm well-travelled, well-read and well-educated to know that maths is correct.