"Jingle bells, jingle bells......"

The bell rings for the second period, although many schools now change the bell to music, but this most traditional bell is more ritualistic, just like you in the exam room, hearing this bell is either relieved or cramped.

The students in the hallway also walked slowly to the classroom, where they also took out math books, math papers, and notebooks.

As usual, the students of the first class of the third year of high school quietly waited for Teacher Huang, who came to teach them.

Su Chen walked briskly to the fifth floor, I have to say that there are quite a lot of stairs in this school, I ran in the morning before, and now my feet are still a little sore.

Su Chen finally climbed to the fifth floor, looking at the empty corridor, and the classrooms were as quiet as cicadas, it seemed that the school style was still good, only the sound of the female teacher's high heels came from a distance, which was quite pleasant to Su Chen's ears, but this sound was like a nightmare to the students.

Su Chen exhaled, straightened his clothes, and strode towards the first class of the third year of high school.

As soon as Su Chen walked into the classroom, there were sounds of surprise in the classroom.

"Hey, why is the PE teacher here?"

"Isn't this yesterday's PE teacher? How did he get here? ”

The girls chattered and whispered.

Only Gong Nana, who had seen Su Chen in the morning, did not make a sound, although she also wanted to know why Su Chen came. But as a class leader, she still knows how to be disciplined.

"Nana, do you know why?" A bun-faced girl with a little baby fat asked Gong Nana.

This girl is Gong Nana's tablemate, called Zhou Xiaoxiao, because she is a little baby fat, and she likes to tie the head of the ball, her classmates like to call her xiaolongbao, of course, the reason why she is called xiaolongbao instead of big steamed buns and the like is mainly based on the fact that several male classmates in the class observed her ups and downs in an indescribable place, and collectively gave her the nickname "xiaolongbao"!

"I don't know." Gong Nana replied truthfully in a low voice.

"Did you change classes?" The girl named Zhou Xiaoxiao suddenly opened her eyes wide, as if she had guessed something, and said happily.

"Oh~~~! It's time for gym class! "The boys sitting in the back row of the classroom are not as quiet as the girls, and the first thing that comes to mind when they see Su Chen coming in is that they don't have to take math classes, they can go to physical education classes to play basketball, as long as they don't have to sit in the classroom, they are all happy, so now they are very happy, and they don't abide by the discipline of class.

Su Chen walked to the podium, put the math study book on the podium, and then looked at the people in the classroom.

"Be quiet, listen to me!" Su Chen raised a hand and pressed it downward, signaling everyone to be quiet.

Suddenly, the classroom fell silent.

"That's the case, your teacher Huang is sick and needs to go to the capital for treatment, I will teach you this class this morning, and who will teach you in the future math class will not be decided until the school meeting at noon is over, but this section will be taught by me." Su Chen explained the matter succinctly.

"Teacher, teacher, is that a gym class?" The tall boy in the back row asked, holding his hands high.

"That classmate, put your hand down first, I can see that you don't need to lift so high." Su Chen motioned to the boy in the back row to put down his hand and said.

"Hahaha", the classmates in the class heard Su Chen's words, and when they looked back and saw the tall boy's actions, they also laughed.

Su Chen: "This class is still a math class, although I am a physical education teacher, I still have the confidence to teach your math courses." ”

"Alas!" After hearing this, most of the students in the class were deflated, thinking that they could relax, but they never thought that they would still take math class.

"You may not believe it, but our math is taught by PE teachers." A classmate paraphrased a sentence on the Internet and made the surrounding classmates laugh.

"Okay, let's take classes seriously, where did you Teacher Huang tell you?" Su Chen asked again after calming the deflated student.

"Definite integrals. However, there was a mock exam paper yesterday, and the teacher hadn't finished commenting on it. The classmates said babblingly.

Su Chen also listened to a general idea, high school elective textbooks also learn calculus, but it is not deeply involved, that is, to learn the derivative of the function and the root of the equation when the equation is equal to zero or the like.

However, I am only taking a substitute for a class, and since they still have a test paper that has not been completed, it is good to simply explain the test paper to them. Thinking of this, Su Chen said: "Okay, let's take out your unfinished paper, and we will comment on the paper in this class." ”

"Somebody give me a roll, and then look at it with my tablemates." Su Chen found that he didn't have a scroll again, so he asked.

At this time, Gong Nana stood up, picked up her scroll and walked towards Su Chen, then handed the scroll to Su Chen and said, "Teacher, you can use mine." With that, he went back to his seat.

Leave a group of people to watch, what's wrong with the class leader? She won't be so active before, learning is her first priority, as long as she doesn't take the initiative to ask her, she won't take the initiative to contribute, and it can't be said that Gong Nana doesn't know how to share knowledge with her classmates, but Gong Nana's grades are already very good, and she has a lot of things to do, if you don't take the initiative to explain or borrow things from her, she won't take the initiative to help others, which is also human nature.

So she was a little too active today, and her classmates were a little uncomfortable for a while.

"Thank you. You can take a look at it at the same table with you" Su Chen took the test paper and gave Gong Nana a smile back.

Su Chen picked up the mock exam paper and looked at it, and after reading the previous multiple-choice questions, it felt very simple.

"What do you think are the multiple-choice questions that need to be discussed?" Because there was no math score statistics table for their class, it was not clear what they were wrong, so Su Chen asked directly.

"Question 3, Question 5, Question 10......" The classroom suddenly resounded with various voices. However, most of them focus on these three questions.

There are a total of 12 multiple-choice questions in this mock test, with a 5-point multiple-choice question and a total score of 60 points. That's a big deal.

"Okay, the third question is, I'll take a look." Su Chen said.

The third question is a trigonometric function problem, Su Chen glanced at it, didn't say the answer, and directly picked up the pen and explained it on the blackboard.

In less than a minute, Su Chen finished explaining.

"Got it? Such a simple question should not be wrong, just put the formula above to get the answer. Saying that, Su Chen wrote out all the formulas of trigonometric functions on the side of the blackboard.

The students below are now starting to believe that this PE teacher is really qualified to teach them mathematics, and that a PE teacher can write all the formulas of trigonometric functions, which cannot be faked. Many of them didn't memorize it completely, and some of them even opened the book to find out how the formula was compared with what Su Chen wrote on the blackboard.

"The student who made the mistake in this question should write down these formulas in a notebook. Then find a time to memorize it all. The next time you encounter this type of question, just take the formula and put it on it. Su Chen put down the pen after writing the formula, looked at the students below and said.