My college had a decent-sized contingent of Bulgarian & Romanian international students. The difference in their math abilities upon entry was striking. While most of my American-born classmates struggled in discrete math, linear algebra, and vector calc, my Bulgarian friend was like "I learned this when I was 9." They were frequently tapped as TAs by the professors, because they understood the material on a level th…
I'd be wary of forming an opinion on foreign education systems from international students, as they're generally of more privileged extraction compared to the unwashed masses who can't afford to study overseas.
*If they don't come from the Americas