They're already in university, and the primary school system is only just starting out?

Seeing Liang Xiaodong's dejected look, Han Sibo seemed a little guilty and thought for a moment before saying, "How about this, I'll go talk to Ge Chi from the next class. He's better at math than me, maybe he already has a solution. Hurry up and figure this out, then I'll go play badminton with you."

However, upon hearing the name "Ge Chi," Liang Xiaodong's expression suddenly changed.

He grabbed Han Sibo's shoulder as he was about to get up.

"Wait a minute!"

Ge Chi is from the next class. His grades are comparable to Han Sibo's, and he is even stronger in math. He is the top math student in the grade.

Liang Xiaodong and Ge Chi were not very familiar with each other.

Han Sibo, on the other hand, would sometimes go over the answers and discuss the questions with Ge Chi in the hallway after the exam.

At those times, Liang Xiaodong could only stand idly to the side, unable to get a word in edgewise, like an unwanted accessory.

Many teenagers in puberty have some strange psychological issues.

Seeing my best friend chatting enthusiastically or having a great time with someone else makes me inexplicably a little annoyed.

"No need to look for him," Liang Xiaodong retorted stubbornly. "It's just a stupid math problem, isn't it? I can do it too! Let me see!"

Upon hearing this, Han Sibo turned his head and looked at him with an expression that seemed to ask, "Are you sure?"

Han Sibo knew perfectly well how bad his good friend was at math.

I usually score just over 100 points in exams, which is a stable performance.

Although Liang Xiaodong had a cheat code in that surprise test a month ago, he was the first to hand in his paper and got the highest score in the class, which really made him proud.

But the good times didn't last long. In the final exam, he was brought back to reality, and his score was still mediocre.

However, seeing Liang Xiaodong's unconvinced look, Han Sibo couldn't bear to call him out on it. He simply pushed the handout with the questions written on it over to him silently.

"Here, this is it."

[Given that non-negative numbers a, b, c, d satisfy a + b + c + d = 6, prove that: (a - b)(a - c)(a - d)(b - c)(b - d)(c - d) ≤ 27]

"..."

A subtle silence suddenly fell over the atmosphere.

Liang Xiaodong stared at the question for twenty seconds, then decisively gave up struggling.

He silently picked up his phone, unwilling to give up, and tried searching online, hoping that some expert might have shared a solution.

"Stop searching," Han Sibao's voice came softly. "If you want to find it online, I've already searched, and there's nothing. By the way, I've also tried using AI, and it didn't work either."

Liang Xiaodong froze, then reluctantly put down his phone.

His eyes darted around, and suddenly he remembered something, slapping his thigh hard.

"No problem! I'm a bit of a shady character, I'll get someone to help me!"

"You're not thinking of asking about your grandfather, are you?" Han Sibo guessed. He knew that Liang Xiaodong's grandfather was an academician of the Chinese Academy of Sciences, a leading figure in academia.

"No," Liang Xiaodong shook his head.

Although he is playful, he is quick-witted and can distinguish between what is important and what is urgent.

My dad just mentioned it yesterday, saying that Grandpa had important business in the capital. He wouldn't dare bother the old man with such trivial matters.

He thought of the salted fish seller who had helped him with the surprise test last time.

"Wait," Liang Xiaodong winked at Han Sibo, a mysterious smile on his face, "and see just how wide your Dong-ge's connections are."

He skillfully opened the Xianyu app, found the seller from last time in "My --> My Transactions --> My Purchases", and silently prayed that the other party would be online.

He sent a message: 【Boss, are you there? I need help urgently!】

Unexpectedly, a reply popped up in the chat box almost immediately.

[Seller]: [In]

Reply instantly!

Liang Xiaodong was overjoyed. Without saying a word, he took a picture of the question and sent it over. Then he quickly clicked on the link that the other party had posted, which was for "high school math tutoring". He left a message asking the other party to change the price to 100 and paid without hesitation.

After doing all this, he slammed his phone on the table and proudly raised his chin at Han Sibao.

Han Sibo looked at him with suspicion, and began to have doubts in his heart.

Less than twenty minutes later, Liang Xiaodong's phone rang.

The seller sent two pictures.

When Liang Xiaodong opened it, wow, it was filled with dense mathematical symbols and derivations, neatly written across two whole pages.

Without even looking at it, he forwarded the picture directly to Han Sibo's WeChat.

"Done."

Han Sibo looked at the two pictures in the WeChat message and became even more puzzled.

So short a time? This proof problem is so difficult, could Liang Xiaodong's helper really solve it in a flash?

What level of skill is that? Even the best math teacher in the school couldn't be that fast!

Filled with suspicion, he clicked on the image, picked up a pen, and began to examine it while simultaneously calculating on a draft paper:

The equality conditions are: a = 4cos^2(pi/18), b = 4cos^2(5*pi/18), c = 4cos^2(7*pi/18), d = 0.

The first step, f(a, b, c, d) ≤ 27, is equivalent to abs(f(a, b, c, d)) ≤ 27.

Since abs(f(a, b, c, d)) is symmetric about a, b, c, d, we can assume without loss of generality that a ≥ b ≥ c ≥ d.

It is clear that abs(f(a, b, c, d)) ≤ f(a + d, b, c, 0).

Therefore, the problem becomes: nonnegative number a + b + c = 6. Proof:

(a - b)(a - c)(b - c)abc≤ 27.】

[The second step is to set f (a, b, c, λ)=(a - b)(a - c)(b - c)abc -λ(a + b + c - 6)....]

.......

Liang Xiaodong didn't disturb him, but sat next to him scrolling through his phone and waited quietly.

Time passed by, second by second.

An hour later, Han Sibo finally let out a long sigh of relief and put down his pen.

A sudden flash of enlightenment crossed his face, which was then replaced by an almost intoxicating astonishment.

"Dongzi," he looked up, his eyes filled with disbelief as he stared at Liang Xiaodong, "the person you found is amazing!"

"His solution to this problem was incredibly clever. He restricted a, b, and c to the first quadrant, transforming the problem into a plane formed by a, b, and c within the first quadrant of a three-dimensional coordinate space. As time d increases from 0 to 6 seconds, the plane continuously shrinks and moves closer to the origin. It's both elegant and concise—amazing! How did you come to know such a genius?"

Liang Xiaodong spread his hands, a mysterious smile on his face.

"I met him through money."

Han Sibo: "?"

......

June 24, Tuesday, before 6 a.m.

Chen Lin carried fresh vegetables he had just bought from the market and walked into the "Nanlinyuan" residential community.

He looked down at the still-damp cement pavement beneath his feet and couldn't help but complain inwardly. The rainy season in Jiangdu was just as annoying as he remembered from his childhood; the air was damp and clinging to his skin, making him feel indescribably uncomfortable.

It's said that it will continue to rain for the rest of the week, but luckily the weather cooperated and it was cloudy when I went out today.

Yesterday, both of Chen Lin's parents went to work, and it was raining outside, so he was too lazy to go out and just stayed home all day, taking the opportunity to study how to write neural networks in Python.

That thing is the underlying logic of the big model of artificial intelligence. He figured he would definitely have to learn it in the future, so he might as well start learning about it now.

Just as they were getting to the crucial point of their research, the salted fish, who had been silent for a long time, suddenly sent word.

Chen Lin thought it was another big order for consultation, but when he clicked on it, he found it was from the high school student named "Black Whirlwind is not McFlurry" from last time.

I placed this order just for a single question.

Okay, a hundred yuan is still money.

Chen Lin didn't think much of it and took out paper and pen to start calculating.

To his surprise, this problem took him nearly twenty minutes and filled two whole pages of draft paper.

Compared to his usual consultation fee of 880 per hour for design institutes, Chen Lin felt that this job was a huge loss for him.

He was also a little puzzled. Although he didn't have much of a concept of undergraduate mathematics or even more advanced mathematics, he had at least fought his way into Yannan University through the single-plank bridge of the Jiangsu Province college entrance examination.

Twenty-one years later, Jiangsu Province used the same mathematics paper for both arts and science students in the college entrance examination. He still had a good grasp of the scope and difficulty of high school mathematics.

At least he didn't have such difficult questions in high school.

Are all high school students this fussy these days?

However, he didn't intend to delve into it further. After all, for someone with the title of "little mathematician," even the most difficult problems would just require more effort and time.

Once it's done, take a photo, send it to the buyer, and the order is considered closed.

Chen Lin snapped out of his reverie and put those thoughts behind him.

Before he knew it, he had arrived at the old-fashioned apartment building where his grandparents lived. The hallway was dimly lit, the paint was peeling, and there was a smell of bygone days in the air.

They lived on the fourth floor, where there was no elevator. Chen Lin walked up floor by floor. Over the years, apart from becoming a bit more dilapidated, everything remained the same.

Chen Lin's maternal grandparents had three daughters, and his mother, Lin Xiaoqi, was the second oldest.

My maternal grandfather was a retired senior cadre, and my maternal grandmother was an ordinary worker. They should have been living quite comfortably on their pensions alone.

Two years ago, my grandfather underwent major surgery for lung problems, and his health has deteriorated since then.

To make matters worse, my grandmother also showed early symptoms of Alzheimer's disease, and her memory deteriorated significantly.

After discussing it, my mother and her two sisters decided to pool their money to hire a 24-hour live-in housekeeper for our parents.

Then, the three of them took turns, each coming to take care of the elderly couple for two days a week, mainly cooking for them, bathing them, and supervising them to take their medicine on time.

In the past, Chen Lin always came with his mother.

Later, he gradually started choosing days when his mother and her two sisters were not home. He wanted to keep them company when their children weren't around and they felt lonely.

When he got home on Saturday, he asked his mother about her work schedule for the week and learned that Tuesday was a free day.

"Knock knock knock".

Chen Lin knocked on the door.

Soon, the door opened, and it was the live-in auntie. When she saw Chen Lin, she smiled kindly and stepped aside to let him in.

Grandfather sat in a wicker chair in the living room, covered with a thin blanket. He was weak and it was difficult for him to stand up.

But he was still pleasantly surprised to see Chen Lin enter. He straightened up slightly and waved to Chen Lin.

Grandma always thought Chen Lin was still in high school in Jiangdu.

Last summer vacation, Chen Lin came back to visit his parents and tried to correct his grandmother when she said he was already in college. But after realizing it was useless, he gave up and now he just goes along with what she says.

Chen Lin put down the groceries he was holding and chatted with the two elders for a while. He mainly took out his phone, found some current affairs news, and read it to his grandfather word by word.

He remembered that when he lived at his maternal grandfather's house as a child, his grandfather loved to read newspapers, and there was a small room specifically used to store newspapers.

Later, after smartphones came out, Chen Lin told him that the information on the phone was faster and more abundant than that in the newspaper. So every time he visited his grandfather, Chen Lin would read the news on his phone to him for a while.

Around 10:30, he went into the kitchen, took out the leftovers his aunt had left in the refrigerator yesterday, heated them up, and then used the ingredients he had just bought to make scrambled eggs with tomatoes and braised eggplant with green peppers.

After the meal was prepared, Chen Lin and his aunt carefully helped the elderly couple to their seats at the dining table.

The four people sat down together and began to eat.

Grandma has no problem eating; she has a good appetite and eats very well.

Grandpa's hands trembled even more severely than they had six months ago, and he couldn't pick up food properly.

Just as the aunt was about to step forward to help pick up some food, Chen Lin stopped her.

"I'll do it."

He put down his own chopsticks and devoted himself to taking care of his grandfather.

Wherever his grandfather's gaze fell, he would pick up that dish and put it in his grandfather's bowl.

After his grandfather had finished eating, Chen Lin picked up his own bowl of rice, which had already cooled down, and quickly began to eat.

After finishing their meal, the two elders prepared to go back to their room for a nap. Chen Lin cleaned up the dishes and also got ready to say goodbye and go home.

"Xiao Lin," his grandfather suddenly called out to him.

He gestured for the aunt to take a red envelope from the drawer of the TV cabinet and hand it to him.

Grandpa stroked the red envelope with his trembling hands and then handed it to Chen Lin.

"Take it, take it..."

Chen Lin quickly waved his hand: "Grandpa, no need, I can earn money myself now."

Grandpa wouldn't listen or argue; he just stubbornly held up the red envelope, repeating the same phrase over and over: "Take it, take it..."

The grandmother, standing nearby, chimed in, "Yes, high school students study so hard, why would they want to earn money? Take this, use it to buy yourself some treats."

Chen Lin sighed softly to himself.

He thought he should accept the red envelope first and then discuss with his mother about using the money to buy some new appliances for his grandparents' house.

Having made up his mind, he stopped refusing, reached out, and took the heavy red envelope from his grandfather's hand.

However, the moment his fingertips touched the red envelope, Chen Lin's body suddenly stiffened.

A series of cold system notifications popped up in front of me.

[A red envelope has been detected that the host has received from an elder!]

For children, saving is the best way to manage money!

[Task Requirements: Receive red envelopes from elders and save them, accumulating to over 2000 yuan!]

[Award Title: Junior Financial Planner]

[Little Financial Advisor: Your Net Worth Grows by 10% Every Month!]

……

[It has been determined that the host has received red envelopes from elders and has saved over 2000 yuan!]

[Mission Completed! Rewards Issued!]

Stepping out of his grandparents' building, Chen Lin checked his system and, sure enough, he had acquired a new title:

【小小理财师：你的净资产每个月增长10%！（当前净资产：32832.5)(距离下次净资产增长： 155：57：31）】

An idea instantly popped into Chen Lin's mind: "No need to hesitate! Immediately use the little red flower to enhance this title!"