First of all, we must have confidence and overcome our fears. Since the curriculum standard requires us to learn the function of junior high school, it shows that the Ministry of Education has fully demonstrated and justified the learning function of junior high school. So we are fully capable of learning functions well.

In order to understand the concept of function correctly, we will use analytic expressions and images to understand the function. When learning functions, we must firmly grasp the concept of functions. A function is the relationship between two variables. When one quantity changes, another quantity changes, and the change of one quantity causes the change of the next quantity.

Students can understand that "the quantity that changes first is called independent variable, and the quantity that changes later is called dependent variable". We can use the relationship between tree and shadow to understand the relationship between two variables in a function. In other words, the movement of trees leads to the movement of shadows. "Tree" is equivalent to independent variable, and "shadow" is equivalent to dependent variable. Through simple life examples, we can better understand the relationship between the concept of function and variables.

Attach importance to the idea of "combination of numbers and shapes" in the second grade function learning;

The thinking method of combining numbers and shapes is an important thinking method in junior high school mathematics. Mathematics is a science that studies quantitative relations and spatial forms in the real world. The combination of numbers and shapes is to solve mathematical problems through the correspondence and transformation between numbers and shapes, including two aspects: helping numbers with shapes and solving shapes with numbers. It can simplify complex problems and concretize abstract problems.

In the first grade, let students contact with functions, learn the plane rectangular coordinate system, function concept and linear function (proportional function), let students feel the corresponding relationship between function relationship and function image, and experience the important mathematical thinking method of combining numbers with shapes. Learning inequalities and inequality groups in the second grade of junior high school, through the connection with linear functions, further permeates the idea of combining numbers with shapes.

In the third grade, students learn inverse proportional function and quadratic function, so that they can fully understand and master the relevant knowledge of function and realize the application of mathematical model combining number and shape of function in real life. Therefore, in the usual study and practice, we should draw a sketch of the function image on the draft paper to help analyze and understand and simplify complex problems.