2. Studying multiples, positive and negative numbers, rational numbers and irrational numbers will help us understand many life phenomena and make our life more rational;
3. Provide general and effective methods to solve problems-equations and inequalities closer to the prototype of life, and carry out idealized simulation research on the shape of objects in life;
4. Study the trajectory of the object according to the coordinate system and understand the concept of limit;
5. Educate us to study cognitive problems with various methods such as abstraction, generalization and inductive analysis, and then solve relatively simple models.