Qin Ke glanced at Ning Qingyun's pretty crimson face and immediately looked away. He silently said in his heart, "My goal is to become a god of learning and conquer the stars and the sea." Then he took the pen from the girl's hand without looking away.

Take the scratch paper again:

"Generally speaking, for such propositions related to positive integers n, you can try to start from n equal to a certain n0, first use the construction method to construct an object p(n0) that satisfies the meaning of the question, and then pretend to be p(n)

It has been constructed, proving that p(n1) can also be constructed... In this way, we can simplify the complex and find the way to solve the problem. Look, I will take this problem as an example and explain it to you."

As Qin Ke spoke, he explained in detail the two proof methods he had thought up, and compared the advantages and disadvantages of the two solutions.

Listening to Qin Ke's gentle and confident voice, Ning Qingyun couldn't help but glance at him secretly.

The boy's side face in the sun is handsome and full of vitality. Although his naturally curly hair looks a bit messy, his face is clean and there is no smell of sweat on his body. There is only a faint smell of laundry soap from the school uniform, which makes him a bit of a germaphobe.

Ning Qingyun surprisingly didn't feel any disgust.

"The entire proof process can be completed here. Do you understand?"

"I understand. You can actually think of combining induction and construction. It's... really amazing." Ning Qingyun doesn't praise others easily, because there are too few people who can admire her, but the boy in front of her is so good at mathematics.

The level is really beyond her reach, and she won't be convinced.

Qin Ke smiled: "Of course, in specific problems, this proof can be constructive or non-structural, and we cannot stick to the rules...'ever-changing', 'adaptive', 'turning the impossible into possible',"

This is also the fun of doing math problems. Well, let’s do it this way, I’ll just teach you this morning, and how about you teach me English in the afternoon?”

This was the original agreement between the two. Ning Qingyun nodded and said, "Okay."

"What I teach you may be different from what teachers usually teach you. They start with question types, but I plan to start with problem-solving methods. After all, your foundation is very good, so it will be better to start this way..."

Ning Qingyun saw that Qin Ke had been bending down to lecture to her, so she stood up a little embarrassedly: "Why don't you sit down, I'll just stand and listen."

As soon as she stood up, her long ponytail swayed slightly, and the distance between her and Qin Ke became closer. The autumn wind blew by, bringing with it the delicious fragrance of the girl.

Qin Ke couldn't help but think of the question "Brother Ke, does Ning Qingyun smell good" in the "dormitory night talk" by Wang Lixin, the sultry guy in his dormitory? At that time, he lazily replied, "I have rhinitis.

Can’t smell it”.

Of course Qin Ke's nose was fine. Even if there was a problem, the system would turn it into a fine one when it attached - so he couldn't help but secretly sniff a few more times.

I don’t know if it’s the fragrance of shampoo, shower gel or the girl’s own body fragrance, but it smells very good.

Realizing that his behavior was a bit abnormal, Qin Ke quickly and quietly distanced himself, pulled a table and chairs over and joined him at the same table: "Let's put it this way, we don't have to stand."

Ning Qingyun nodded.

When Qin Ke was about to sit down, Ning Qingyun suddenly shouted: "Wait a minute."

"Um?"

"Get out of the way first."

Qin Ke took two steps back inexplicably and saw Ning Qingyun taking out a pack of wet wipes and carefully wiping the tables and chairs he had brought in - these tables and chairs had been placed in the vacant old art room for quite some time.

All have a thin layer of dust.

"Okay, you can sit down."

"Uh...thank you." Qin Ke couldn't help but look at Ning Qingyun a little flattered. This guy actually wiped the tables and chairs for him? This is why when his younger sister Qin Xiaoke wanted to please him and asked him to help with things, he

Just enjoy the treatment, right?

Probably because she was embarrassed by Qin Ke's gaze, Ning Qingyun blushed and defended: "I...I have mysophobia and I can't bear to see dirty things in front of my eyes."

"Thanks anyway." Qin Ke sat down with a smile.

Ning Qingyun rolled her eyes at him, and suddenly thought, aren't she her roommate again? And in this classroom with only two people...

But at this time Qin Ke was ready to start writing and explaining at the same time. Ning Qingyun quickly gathered her thoughts and said, "Wait a minute."

She reached for her schoolbag and took out a beautiful notebook and a pen. She was ready to record the key points before saying, "Okay, you can start."

Qin Ke couldn't help but sigh when he saw this: "You really deserve to be Ning Qingyun."

Ning Qingyun tilted her head slightly and asked in confusion: "What do you mean?"

"Literally. Okay, let's get started..."

At present, Qin Ke started from the "reduction" problem-solving method of the Mathematical Olympiad, and continued to extend it with examples. Basically, he explained in detail according to the knowledge context instilled in him by the system.

Ning Qingyun had never heard such a novel explanation. Qin Ke not only explained one method and one example question, but also explained all possible scenarios and question types that this method could be used in, and strung them together into clear sentences.

knowledge context.

This is somewhat similar to Ning Qingyun's usual learning method, so Ning Qingyun accepted it quickly and studied very seriously.

One of them concentrates on teaching and the other learns seriously, completely immersed in the ocean of knowledge, and even forgets the existence of time.

Suddenly I heard a cough from the direction of the door.

The two of them came back from studying and looked at the door, seeing that it was Lao Zheng who was coming.

Only then did Ning Qingyun notice that she was very close to Qin Ke, with their shoulders almost touching each other. She couldn't help but feel her face getting hot, and she hurriedly sat up straight to put some distance between them.

But Lao Zheng shouted to her outside the door: "Classmate Ning, come here, there is a missing part in the Mathematical Olympiad registration form you submitted last time. You participated in the preliminary round last year and entered the top ten. This will be in the Mathematical Olympiad."

Write it in the experience column..."

"Okay, Teacher Zheng." Ning Qingyun stood up, and Qin Ke also stood up.

Now they are sitting at the same table. His seat is outside, while Ning Qingyun's seat is inside, against the wall. You have to pass by him to get out.

Qin Ke stood up and left his seat. Ning Qingyun whispered "Thank you" in a low voice and hurriedly left Qin Ke, bringing with him a gust of fragrance.

Qin Ke couldn't help but rub his nose. Well, I can't smell it. Well, the stars and the sea are so beautiful.

In order to divert his attention, he stretched out his body habitually and moved his hands and feet.

I don't know whether Ning Qingyun touched her schoolbag when she got up too hastily, or whether Qin Ke accidentally touched the table when she stretched her arms and legs. Anyway, just after Ning Qingyun walked away for a while, her schoolbag fell out of the drawer.

Qin Ke caught sight of it from the corner of his eye, and without even thinking about it, he stretched out his hand and bent down to stop it, but in the end he took a step too slowly and his schoolbag fell to the ground with a bang.

This beautiful and clean pure white schoolbag immediately became covered in dust.

Hey, that guy with mysophobia will be sad if he sees it.

Qin Ke shook his head, squatted down and picked up his schoolbag.

The schoolbag was not zipped, and when it fell down, several books fell out, and one of them was opened.
Chapter completed!