Why should we learn mathematics well when studying economics? Man Kun gave the following reasons: 1. A student who is interested in becoming an economist in policy research will be recommended to enter the best research institute or university he or she can enter. And these universities will definitely want to see many math courses on your undergraduate report card, so you must do so and study math. 2. Every economist needs to have a solid foundation of economic theory and mathematical economics, even if you don't plan to be a theoretical economist or a mathematical economist. If you can't master the mathematical language well, you can't have a solid foundation in these fields. Sometimes, you need math in your work. Policy economists especially need to read those academic articles to find out which research viewpoints are relevant to policy making. And these academic articles will use a lot of mathematics, so you need mathematics to arm your mind so that you can understand these papers. Mathematics is a good thinking training. It will make you a rigorous thinker. Mathematics has indeed played a more important role in the graduate class. 6. Math class is a long-term IQ test. We use mathematics to screen out really smart people.