Oh no! I've only been a freshman and I've already been targeted by a mean upperclassman.

Chapter 155: The exam is over!

Wang Qiang's advanced mathematics homework problems were spread out on Li Chen's desk.

Fifteen questions. Three were wrong.

It's down by half compared to last time.

Li Chen drew a circle next to the limit calculation in question seven with a red pen.

"You can't directly replace it with an equivalent infinitesimal here. When the denominator involves addition or subtraction, you need to separate the operations."

"Take it apart... that's what we'll do first—"

"First replace sinx with x, then replace 1-cosx with x²/2. The step you wrote changed the entire denominator, which is not precise enough."

Wang Qiang grabbed a handful of hair. He stared at the question for ten seconds.

"I understand."

"Do you really understand, or are you just trying to fool me?"

"You really understand. This time it's for real." Wang Qiang slapped the table.

Li Chen pushed the homework back. "Do questions 9 and 12 again yourself. Take a picture and send it to me when you're done."

"tonight?"

"Now."

Wang Qiang let out a groan, but didn't leave his chair. He opened his notebook and began calculating.

Zhao Zixuan poked half his head out from the top bunk. "Li Chen, you're stricter with Wang Qiang than the homeroom teacher."

"The homeroom teacher doesn't need to report to his sister-in-law."

This sentence made Wang Qiang pause, his pen still. He didn't complain anymore.

陈默推了一下眼镜。「根据王强近七天的错题率曲线，从第一天的60%下降至今天的20%，斜率为-5.7%/天。按此趋势外推，考试前可压至10%以内。及格概率已从31%上升至87%。」

Zhao Zixuan rolled his eyes. "Speak like a human being."

"Wang Qiang can pass."

Wang Qiang straightened his back a little.

Li Chen returned to his desk and opened the study plan PDF that Yan Xi had sent him.

Today is the fifth day before the exam.

The schedule reads: 2 PM to 5 PM - Advanced Mathematics Comprehensive Mock Exam (Set 1); 6 PM to 9 PM - Final round of Physics Electromagnetism; 9:30 PM to 10 PM - Rest.

The small print on the last line has remained unchanged.

"You can call me."

He printed out the mock exam paper. A4 paper. Twelve pages.

The timer is set to 120 minutes.

Start.

He put down his pen forty-seven minutes later.

I checked it once.

144 points. The point deduction was made in question 19 regarding the substitution in the double integral. The sign of the Jacobian determinant was reversed.

This matches the type of high-frequency error that Yan Xi pointed out—symbol problems, which ranked second in frequency.

He flipped back to the error analysis sheet.

The first place was for calculating carry-out omissions, which occurred seven times.

The second most common error was a misspelling of the plus or minus sign, which occurred five times.

She tallied it up one by one from seventeen assignments.

Li Chen marked the mistakes on the test paper with a red pen. He then took a picture.

Send it to Yan Xi.

Twenty seconds.

[Yan Xi: This is the third time.]

[Li Chen: I know.]

[Yan Xi: This is for checking things after you finish the exam. I made a checklist for you.]

An image file pops up.

Handwritten.

Her handwriting.

The list contains five items.

Rule 1: Check all plus and minus signs.

Article 2: Check carry and borrow.

Article 3: Check the direction of the upper and lower limits of integration.

Article 4: Examine the sign pattern of the determinant expansion.

Fifth: Take a deep breath. Don't rush.

Li Chen stared at the fifth point.

He saved the picture to his album and added it to his favorites.

[Li Chen: Received.]

[Yan Xi: Where's your thesis?]

[Li Chen: I don't have a thesis.]

[Yan Xi: The question is about the paper you helped Wang Qiang revise. Did you read his short essay on Marxist theory?]

Li Chen turned his head.

Wang Qiang was still engrossed in writing advanced mathematics.

"Wang Qiang."

"Um?"

"Have you written your short essay on Marxist philosophy?"

Wang Qiang stopped writing.

"...What short essay?"

"Final paper for Marxist Philosophy course. 1500 words. Due next Monday."

Wang Qiang's expression froze for three seconds. Then he suddenly pulled out his phone, opened the teaching platform, and scrolled through it for a long time.

His expression changed.

"How come I didn't know this existed???"

Zhao Zixuan held his phone out from the top bunk. "It was sent three times in the group chat. Didn't you see it?"

"I thought it was a group chat message..."

Li Chen replied to Yan Xi's message.

[Li Chen: He didn't know there was a paper.]

Four seconds.

[Yan Xi: As expected. Keep an eye on him as he writes. The topic should be any principle of dialectical materialism that connects to real-world situations. Don't let him copy from the internet; it won't pass the plagiarism check.]

Li Chen locked the screen.

"Wang Qiang."

"Um?"

"Finish the first draft of your Marxist theory paper before 11 PM tonight. Send it to me."

"11 o'clock?? I haven't even finished my advanced calculus yet—"

"Write your paper first. Do the calculus problems tomorrow morning."

Wang Qiang opened his mouth. Then he closed it.

He knew this was his sister-in-law's order.

The next four days.

Li Chen's schedule was set by Yan Xi's plan. The error was no more than ten minutes.

We go for a morning run on the playground at 6:50 every morning. After the run, we eat breakfast together.

He studied in the morning. At noon, he waited for her next to the second pillar on the left side of the lobby on the first floor of the second teaching building.

Yan Xi walked down from the third floor. He was always the first person to catch her eye.

We continued reviewing in the afternoon. We had dinner together in the evening.

It's 9:30 p.m.

The phone rang on time.

Thirty minutes. Not much. Not little.

Before hanging up the phone, Yan Xi would say something.

What will be the first exam tomorrow?

Advanced mathematics.

"Do the problems on Gauss's theorem first. They have the highest point value. Check the signs after you're done."

"understood."

"Go to sleep."

"Good night."

Exam week.

Day 1. Advanced Mathematics.

Li Chen arrived at the examination room fifteen minutes early.

The third row, by the window. His usual spot.

He tried curling his hair. He first glanced at the questions.

There were twelve fill-in-the-blank questions, four calculation questions, and two proof questions.

The fill-in-the-blank questions took 18 minutes. The calculation questions took 35 minutes. The proof questions took 20 minutes.

Forty-seven minutes remain.

He turned back to the first page.

Check from the beginning.

According to the list written by Yan Xi.

First, the plus or minus sign. Check each question one by one. A minus sign was missing in the eighth fill-in-the-blank question. It has been corrected.

Second, carry-over. No problem.

Article 3, Limits to Integration. The upper limit in the second-to-last calculation problem was written backwards. It has been corrected.

Fourth, the determinant symbol. Used in the last proof. That's right.

Article 5.

Take a deep breath. Don't rush.

Li Chen's gaze lingered on those five words for two seconds.

He closed the exam paper.

Submit your paper ten minutes early.

I walked out of the exam room. My phone vibrated.

Group 302.

[Wang Qiang: Is the answer to question 14 3π/2?]

[Zhao Zixuan: I wrote π.]