Many Americans find maths to be awkward to say, so we use math as an alternative. Also, what the hell is a "regular Americano"? I have lived in the US all my life and I have never once heard that phrase used for any reason at all. Train station seems perfectly valid, as does shopping cart. "That'll learn ya" is only seriously used in specific regions of the US and it is used elsewhere because it is hilarious. I have never heard "two-time" or "three-time" used in the way described by the second person, "Oftentimes" is never one word, "Eaterie" has never been spelled with an "ie" in the US, and I had no idea that former prime minister Gordon Brown cared so much about our numerical idiosyncrasies. Also, I use "season" for TV when describing an American program, and "series" when describing a British programme. However, I agree zealously about "could care less" when used in place of "couldn't care less".