If you really want to choose the most important, it must be a function.

Functions are important in the following ways:

1, function content accounts for 1/3 of high school content,

2. As our basic calculation skills in solving problems: solving equations, solving inequalities, and directly integrating high school functions.

3. The thought of function is only one of the seven thoughts of senior high school mathematics, and it is also a mathematical thought that most students can't form.

A deep understanding of the thought of function allows us to look at things and phenomena in life with a dynamic eye.

4. Function is also an important content in the content of college entrance examination.

5. Other problems can be solved by function learning.