It's American K-12 education that isn't up to world standards. That means the American secondary school graduates entering tough college programs have more catching up to do than the (much more stringently selected) international undergraduates at American colleges. See the book Knowing and Teaching Elementary Mathematics

http://www.amazon.com/Knowing-Teaching-Elementary-Mathematic...

(or its review by mathematician Richard Askey)

http://www.aft.org/pubs-reports/american_educator/fall99/ame...

for example of ways American primary education could do better.