Making Money with Mathematics!

Fang Jiaxue nodded, seemingly putting her worries to rest. The two stood in the hallway without speaking for a moment, and things grew a little quiet.

Qi Hao wasn't very good at making awkward small talk with girls. He was about to find an excuse to slip away when Fang Jiaxue spoke up.

"Actually, Xiao Ze wasn't always like this." She seemed to become more talkative because Qi Hao was her age. "His grades were okay in elementary school. He wasn't at the top of his class, but at least he wasn't near the bottom. Then... something happened in our family, and my dad started getting busy with work. He hardly ever looked after us anymore."

Qi Hao understood what she was getting at, but he didn't rush to ask questions. He just listened quietly.

"My dad's incredibly busy. Add up all the time he spends at home in a year, and it's pitifully little," Fang Jiaxue continued. "He's either at the company or away on business. Sometimes he doesn't even come home for the New Year."

"So you're the one who usually takes care of Xiao Ze?" Qi Hao asked.

"Mm. The auntie helps too, but when it comes to discipline..." Fang Jiaxue gave a wry smile. "The nanny never feels comfortable being too strict, so I handle most of it. But I have school too, and sometimes I really can't manage everything."

Qi Hao nodded, understanding Fang Jiaxue a little better.

It really wasn't easy for a college student to juggle her own studies while acting as half a parent and disciplining a younger brother going through his rebellious phase.

"What about your mom?"

"...She's gone."

"I'm sorry. I shouldn't have asked." Qi Hao apologized at once.

Fang Jiaxue shook her head. "It's okay. It's been years. After that, my dad buried himself in work, as if keeping busy meant he wouldn't have to think about those things."

Qi Hao fell silent.

Although he was only a freshman, the hardships of life had made him better able than his peers to understand why adults numbed themselves with work.

Some people drank, some played video games, and some chose to turn themselves into machines that never stopped running. The methods differed, but at their core, they were all ways of escaping pain.

The mood had grown heavy, so Qi Hao decided to change the subject.

"What does Uncle Fang do for a living, to be so busy?"

Fang Jiaxue recovered quickly. When she spoke of her father's work, her tone returned to normal. "He does quantitative investing. I don't really understand the details, but he basically uses mathematical models and computer programs to make financial trades."

Simply put, quantitative investing was stock trading.

But quantitative investing relied on mathematical models, data, and algorithms. Individual stock trading was different; it relied on personal experience.

At this point in Huaguo, quantitative investing was still a rather niche field.

Most retail investors still traded stocks by studying candlestick charts and listening to market tips. Those who actually used mathematics and computers for quantitative investing were either elites who had returned from abroad or science and engineering PhDs from top universities.

Anyone who could establish a foothold in the field and achieve results was, without a doubt, a true expert.

It also meant they were very rich indeed.

Just like Uncle Fang. For people like him, buying a villa was easy.

To be honest, Qi Hao was interested in the field. The paper the system had given him was, at its core, about solving optimization problems in complex decision spaces. The core of quantitative investing was likewise finding optimal strategies amid uncertainty.

The logic behind the two was strikingly similar.

He made a mental note to study up on quantitative investing.

He might be able to use it someday.

He had heard his senior schoolmates say that applying mathematics to finance made money much faster than tutoring.

"All right, it's getting late. I'll head back to school. Before I come next time, I'll prepare some more targeted exercises and try to help Xiao Ze improve even faster."

"Thank you." Fang Jiaxue saw him to the door, a rare, gentle smile appearing on her face. "Really, Xiao Ze was much more serious about his work today than he used to be."

"He's clever himself. I just found the right way to bring it out."

Qi Hao changed his shoes, opened the door, and went outside.

The wind swept the coolness of early autumn into his face. Qi Hao took a deep breath and headed toward the bus stop with a light step.

Before long, he saw that Fang Guoping had transferred him five hundred yuan. He was wondering whether the man had sent the wrong amount when a text arrived.

[Qi Hao, Jiaxue has already told me what happened. I didn't expect Xiao Ze to like you so much, which also proves how professional you are as a tutor. The three hundred yuan an hour we discussed before was actually the standard rate for a trial lesson. Today's lesson went well, so I'll pay you the normal hourly rate. From now on, every hour will be calculated at five hundred yuan. Also, starting next Saturday, could you arrange two-hour lessons for Xiao Ze?]

Qi Hao's mood instantly soared.

Uncle Fang was a man worth knowing!

He liked people who respected knowledge!

He could teach for two hours straight next week, too, which meant he could earn a thousand yuan next Saturday!

Now he wouldn't have to worry about his living expenses.

He had to hurry and tell his mom so she wouldn't have to send him money for living expenses anymore.

After texting her father, Fang Jiaxue returned to the living room, sat down, and poured herself a glass of water.

Her phone vibrated on the coffee table. Her best friend was calling.

"Hello? Jiaxue, want to go shopping? New World Department Store has a sale on lately. I've got my eye on a pair of shoes, and I want your opinion."

The voice on the other end was lively, with a carefree, outspoken air.

"I can't," Fang Jiaxue said, holding her glass as she leaned back into the sofa. "I have to keep an eye on Xiao Ze while he does his homework."

"Fang Jiaxue, say that again?"

"I said I have to keep an eye on Xiao Ze while he does his homework."

"Fang Jiaze? Doing homework?" The voice on the phone rose. "You're not kidding me, are you? The same Fang Jiaze who was ready to flip the table on you the last time you asked him to do five problems?"

"That's him."

"Oh my god, did the sun rise in the west? How did you do it? Did you slip him a love potion or cast a spell on him?"

Amused by her friend's exaggerated reaction, Fang Jiaxue briefly recounted what had happened that day.

"Where did you find this tutor? What's his background?" Her best friend was immediately interested.

"The University of Electronic Science and Technology. He's a freshman, majoring in mathematics."

There was another two seconds of silence on the other end.

"...The University of Electronic Science and Technology? A freshman?"

Her friend's tone clearly changed from delight to doubt.

"I'm not trying to pour cold water on you, but the math department at the University of Electronic Science and Technology isn't well known. Even our math department at Sichuan University could crush theirs."

"He's a freshman and hasn't competed in any contests... Are you sure he's good enough to tutor Xiao Ze? He can handle middle school math, but what if Xiao Ze moves on to harder material later?"

"He explained things well today, and Xiao Ze cooperated."

"Xiao Ze might have cooperated just because he made things interesting, not because he's qualified. Being interesting and being qualified are two different things. Think about it: if his own math foundation isn't solid, what if he leads Xiao Ze into a ditch as he teaches him?"

Fang Jiaxue fell silent.

She certainly thought Qi Hao had explained things well, but her friend had a point too. An interesting teaching style wasn't enough; he also needed real ability.

The tutors they had hired before had all been considered renowned teachers. This was the first time they had hired a college student as a tutor.

"How about this?" her friend suggested. "I've been working on some math competition practice problems lately. Next time, have him try them and see how far he gets. They aren't particularly difficult, but they give you a very clear idea of a person's mathematical thinking ability."

"If he really knows his stuff, he should be able to handle them easily. If he can't, you'll know early on, so you won't end up spending extra money and holding Xiao Ze back."

"But he's only a freshman."

"So what if he's a freshman? I'm a freshman too!"

Fang Jiaxue thought it over. Although the idea felt a little like putting him to the test, it really was a good way to gauge his ability.

"...All right. Send me the problems."

"Hang on. I'll send them when I find them."

Soon after hanging up, Fang Jiaxue received a file from her friend.

They were all competition problems covering topics such as number theory and combinatorics, taken from actual provincial math competitions.

Fang Jiaxue glanced at them and couldn't make any sense of them.

She was a humanities student. To her, mathematics was a language from another dimension.

"For Xiao Ze's sake, I have to do this. I hope he doesn't think I'm deliberately making things difficult for him," Fang Jiaxue muttered to herself, putting her phone aside.

Meanwhile, Qi Hao boarded the bus back to school.

There were only a few people on board. He found a window seat, sat down, and took out his phone to browse the internet.

With nothing else to do, he opened his browser and searched for an introduction to quantitative investing.

Fang Guoping's generosity had made Qi Hao yearn to enter the industry.

There wasn't much information about quantitative investing on the Chinese internet. Most of it consisted of scattered discussion threads on finance forums and a handful of translated articles from overseas.

Qi Hao spent a dozen or so minutes skimming through it, gaining a preliminary overview of the field.

Simply put, the core of quantitative investing was using mathematical models to guide investment decisions.

Traditional investors relied on experience, intuition, and market news to make judgments, whereas quantitative investors relied on mathematical models, statistics, and algorithms.

No wonder the senior who had switched from mathematics to quantitative finance had said it was easy to find a job. So that was why.

Making money with mathematics.

Those words were quietly planted in Qi Hao's mind like a seed.

The most fundamental reason he had joined the mathematics department was that he wanted to be a researcher.

But actual scientific research often required enormous financial backing.

Most of that funding came from the state.

As a result, research directions were sometimes restricted.

Now that he had a Soviet Academic Overachiever System, why shouldn't he find a way to earn some funding himself, improve his family's life, and research whatever he wanted along the way?

Just like Musk abroad.

He had earned his first tutoring fee thanks to mathematics, but Qi Hao considered that small change.

He wanted to be as rich as Uncle Fang.

According to the information available, quantitative investing in Huaguo was still at the cottage-industry stage.

Most of those elites who had returned from abroad were still using linear regression models or simple multifactor strategies, trying to find a hint of order in the chaotic candlestick charts.

But Qi Hao keenly spotted the shortcomings.

"The methods they're using now are a little too clumsy."