While we're on the subject, Americans go to elementary school (kindergarten through sixth grade), then middle school or junior high (grades 6-8 or 7-8 or 7-9, varying), then high school through grade 12.

In some areas of the country, such as where I'm from, middle school is grades 5 and 6, while junior high is grades 7 and 8, sometimes 7 through 9. That's fairly typical, from what I've seen, in the Midwestern states. =D