I am from China and I always thought I am very good at math, because I can get good grades at national Olympiad level math competitions. After I came to America, I realized that I got good grades in China because I internalized the math concepts by doing large amounts of problem sets and it was actually a very slow learning process. In college mathematics courses, I realized that some of my American classmates can grasp new concepts and mental models ways faster than me, without doing much problem sets. We have just been learning math in very different ways.