As American students continue to struggle in math and reading, students in Shanghai who took international exams for the first time outscored every other school system in the world, NBC News reports.The news isn't particularly surprising. A 2009 study showed that U.S. students ranked 25th among 34 countries in math and science, behind nations like China, Singapore, South Korea, Hong Kong and Finland.When Shanghai students took international exams, they came out on top across all subjects.