For example, statements in a set, such as-1, 1, mean that all the elements in the set are greater than-1 less than 1, and the completeness is that numbers between-1 and 1 belong to this set. Of course, these two statements can also be extended to other fields.
Extended data:
Skills to learn mathematics well:
1, mathematics is not only about strength, but also about skills, methods and inductive ability.
2, master the shortest method, pay attention to efficiency when doing problems, and pursue fast and accurate mathematics. If you can finish it in 30 seconds, you should never use 1 minute. If it takes too long, it's okay even if it's right. Maybe you will lose more than you gain in the exam.
3. Listen to the teacher, learn to listen and learn to remember. What I want to hear is the teacher's idea. Why do teachers think so, but they don't? Why? I understand. I don't understand. What is remembered is not how much the teacher wrote, but how much he felt.
4. Communicate with classmates more ways and ideas after class, be good at brainstorming, ask if you don't understand, ask once if you don't understand, ask ten times, don't be shy, feel stupid, and shyness can't solve the problem.
5, do more exercises, do more to know what you don't understand, do more questions that you don't understand, and then draw inferences and summarize the optimal solution of this question according to your actual situation.
6, pay attention to broaden your horizons, boldly try new methods, new ideas, ever-changing math problems, many problems are difficult to solve according to conventional ideas, don't kill your whimsy.