Satisfaction in the student days seems to be relatively simple. Having delicious food, solving a problem, or having someone you like smile at you is enough to make people feel happy.

Although Li Da had already eaten many more delicious noodles with beef and pig's feet added, he still felt satisfied after eating the school's bald noodles (what we call noodles without side dishes here).

This is simple happiness.

However, if another dish of pig's knuckle noodles is placed in front of Li Da, Li Da will definitely choose the pig's knuckle noodles.

When returning to the classroom after eating some noodles, he passed by the school store. Li Da stopped for a moment and decided to go in and take a look.

This is not the first time Li Da has passed by, because the store is the only way to go back to the dormitory or to the canteen. However, Li Da had no money before, so it was naturally difficult to go in.

However, when he went in this time, Li Da didn't find anything he wanted to buy.

Most of the stores in the store are snacks. Li Da doesn't like snacks. It's okay to eat spicy strips once in a while. Li Da basically doesn't touch other snacks.

But now Li Da is probably full and doesn't want to eat anything.

Even though we were here, it was not good not to buy anything, so Li Da took away two lollipops. They were really good, and they cost 50 cents each.

Putting it in his pocket, Li Da walked back to the classroom. Luo Dongqing was already awake. She was reading the revised part of the exercise book that Li Da gave her. She saw that many questions were wrong. Luo Dongqing was also very frustrated.

She was very good at it on the first day, but now she realizes that mathematics cannot be understood by just learning it. The questions she answered were all of the lowest difficulty.

"Here, I'll give you a piece of candy."

Li Da took out the two lollipops and gave the orange-flavored one to her, while he kept the peach-flavored one for himself.

It took a lot of effort to tear open the packaging of this lollipop. After breaking the packaging with difficulty, Li Da stuffed the lollipop into his mouth.

This taste is tooth-droppingly sweet.

Luo Dongqing was still watching Li Da's solution process, and did not go to get the lollipop. Li Da explained: "You have to grasp one key point when doing this kind of question, which is to use the known conditions to derive more conditions, and then use them

These conditions lead to more conditions.”

This is the basic idea of ​​mathematical proof questions. When the conditions are insufficient, conditions must be created. The auxiliary lines are used to create conditions.

Li Da did not tell Luo Dongqing that her solution to the problem was all based on imagination. After all, Luo Dongqing was already feeling very uncomfortable. What she needed at this time was comfort, and ridicule was for those who didn't work hard even though they clearly had no results.

"One technique is reverse reasoning. For example, in this question, you want to prove that one line is perpendicular to another line. You can think about it the other way around, how can you prove that two lines are perpendicular?"

Luo Dongqing fell into deep thought, and then, thirty seconds later, Luo Dongqing shook his head, and Li Da suddenly said helplessly: "A straight line perpendicular to the plane is perpendicular to any straight line in the plane. This theorem can be used. Then, next,

You just have to prove that this line is perpendicular to this plane, right?"

"Yeah, yeah."

Luo Dongqing nodded repeatedly, looking suddenly enlightened, and Li Da asked again: "How to prove that the line is perpendicular to the surface?"

"Prove that it is perpendicular to two intersecting straight lines in the plane."

Luo Dongqing said with a pure smile. It seemed that at this moment, Luo Dongqing felt real happiness.

Li Da put down his pen and said, "You can prove the rest by yourself."

"Uh-huh."

Luo Dongqing nodded, smiled at Li Da again, and said, "Thank you."

"You're welcome."

Li Da behaved a little coldly.

But some people are calm on the surface but are already turbulent on the inside...

Why is this guy so cute?

Could it be said that I am a one-horse tail-controller?

No, no, no, don't smile at me.

Why does she smile so beautifully?

Men really like beautiful eighteen-year-old girls.

These are Li Da's inner activities.

Li Da seemed as steady as an old dog, but in fact he was panicking.

"I'm twenty-seven, and there's nothing wrong with finding a sixteen-year-old girl cute, right?"

But Li Da doesn't want to become a lolicon, but the combination of a single ponytail and a Holly smile is really a bit uncontrollable. You tell me, you usually have a cold face, why are you smiling today?

It makes my heart beat fast. If I have any sinful thoughts, it won't be good!

Li Da suddenly felt that he had become a drama queen. With so many inner dramas, he might just be happier today. He changed his hairstyle, maybe it just changed his mood.

Actually, it was something Jiang Kai said at the door yesterday.

At this moment, Luo Dongqing also proved the question just now without looking at Li Da's answer. As a celebration, she tore off the wrapping paper of the lollipop, stuffed the lollipop into her mouth and held it.

, this lollipop is so sweet.

Luo Dongqing took it out again, smacked her lips, and stuffed the lollipop into it. Seeing Li Da looking at her, she didn't think much and just asked: "Have you finished writing the manuscript?

"

Luo Dongqing took the initiative to ask for Li Da's manuscript. In order to cover up his guilty conscience, Li Da nodded quickly, handed the manuscript to Luo Dongqing, and added: "Class is about to start, don't read in class, listen carefully."

"I got it, Uncle Da!"

Luo Dongqing's title made Li Da a little uncomfortable and said, "Are you giving me a nickname?"

"Yes, you always look old-fashioned and old-fashioned, just like an uncle."

Speaking of this, Luo Dongqing suddenly felt very happy. His nickname was so appropriate.

"I refuse this title. If you call me by my full name, if that doesn't work, call me Lao Li Ducheng."

Li Da doesn't want to be an uncle, because uncle and Loli are the standard match.

"No, I just like this, Uncle Da! Just a little bit..."

Because of Li Da's resistance, Luo Dongqing got angry and stuck out her tongue at him, looking naughty.

Li Da: "..."

Are you a child? You are still a little bit confused!

However, if Luo Dongqing wanted to call him that, there was nothing Li Da could do.

The first class was chemistry, Li Da's weak link. After stopping the quarrel with Luo Dongqing, Li Da previewed the content he was about to learn in advance.

Luo Dongqing got the manuscript and saw that class hadn't started yet, so he took it and read it for a while. When the bell rang, Luo Dongqing happened to look at the place that made him feel itchy.

Li Da reminded: "Have a good time in class!"

"oh!"

Luo Dongqing agreed and put the manuscript aside, but she was bored listening to Yao Bing's lecture, and she was thinking about the plot of the story, so she quietly took Li Da's manuscript over and read it.

.

Li Da shook his head. Alas, it is not that easy to make a bad student fall in love with learning.

However, let her go, Li Da didn't say anything.

Since we are all sitting in the seats reserved for bad students, it is normal not to study hard.
Chapter completed!