I’m an Australian teacher who has also taught the U.K. curriculum (so I have textbooks from both countries) and, based on these comments you mention, have also Googled some U.S. textbooks, and I’ve yet to see any Maths textbooks that teach it “the other way”. I have a very strong suspicion that it’s just a lot of people in the U.S. claiming they were taught that way, but not actually being true. I had someone from Europe claim the way we (and the U.K.) teach it wasn’t taught there (from memory it was Lithuania, but I’m not sure now), so I just Googled the curriculum for their country and found that indeed it is taught the same way there as here. i.e. people will just make up things in order not to admit they were wrong about something (or that their memory of it is faulty).