<p>A part of the last part above is probably because some countries cover what we consider late high school or even early college course content at an earlier stage of education. For instance, calculus which would often be a late high school/early college course is usually covered at the junior high level for those on the college-prep track in the ROC(Taiwan). This was a sore point with mom as she took calculus in the mid-'50s as a high school sophomore at a remedial high school.</p>