The Overachieving Little Husband of the Top Scholar’s Household - Chapter 81: An Introduction to Mathematics · Equations

Chapter 81: An Introduction to Mathematics · Equations

After the Shangsi Festival, the days continued to pass by peacefully and productively. Qiu Huanian was preoccupied with matters concerning Qimin Bookstore and had tried to arrange several meetings with Su Xinbai, but none had been successful.

It wasn’t until over ten days later that they finally met again at Kuzhou Tower.

As soon as Su Xinbai walked in, Qiu Huanian propped up his chin and studied him.

On the surface, Su Xinbai hadn’t changed much. He still had a cold and detached face, an arrogant expression, and courteous manners.

However, the gloom between his brows had completely dissipated, and his eyes now occasionally showed traces of gentleness.

Qiu Huanian smiled and said, “Finally, the busy man has arrived. What have you been up to these days?”

Su Xinbai didn’t reply, his face slightly flushed.

For the past ten or so days, Zhu Jingcheng had stayed home every night, clinging to Su Xinbai incessantly. A man in his twenties was in his prime; once the seal was broken, there was no turning back. Su Xinbai’s waist ached daily, and his thighs were so numb he could barely walk.

Zhu Jingcheng had proven through action that the madness of their first night together had nothing to do with alcohol.

Su Xinbai, being prideful and afraid that Qiu Huanian would tease him if he found out, had simply stayed home and avoided going out.

Yesterday, Zhu Jingcheng had finally been called away for business outside the city, giving Su Xinbai a chance to leave the house today.

Seeing his expression, Qiu Huanian realized that something had clearly progressed in their relationship, but he hid his amusement in his eyes.

Su Xinbai cleared his throat lightly. “Your mathematics book has already been carved onto printing blocks. This is a sample copy the manager brought over. See if there’s anything you want to change.”

Qiu Huanian took the sample. He had written the book in concise language, with text that was clear and succinct. The entire book was only two fingers thick and was bound with hemp thread.

On the dark blue cover was the title An Introduction to Mathematics · Equations. Inside, the text was neatly arranged, accompanied by necessary illustrations.

The craftsmen at the Zhu family’s printing house were experienced and highly skilled. The block printing was excellently done and met all of Qiu Huanian’s specifications.

Qiu Huanian nodded. “Print it just like this. I’m taking this sample copy. I promised to give it to someone.”

Su Xinbai said, “Once the book is printed in bulk, I’ll send some copies to the educational administration of Liaozhou and to all the major academies. You should also submit a memorial to the emperor and present a few copies.”

Qiu Huanian hadn’t thought of that. As a titled lord, he indeed had the right to submit memorials. But whether the emperor would personally read it, he couldn’t guarantee.

“These suggestions—surely they didn’t come from you?” Su Xinbai was never one to care about such things.

Su Xinbai slightly averted his gaze. “It was Jingcheng who reminded me.”

“Not calling him ‘Eldest Young Master’ anymore?”

Su Xinbai directly changed the subject. “Writing a book is a merit in itself. Since the emperor granted you your title for your agricultural book, if you now present this mathematics book, it would be another merit.”

“If the emperor gives even a few words of praise, it will help the book spread more easily.”

In those times, mathematics was generally undervalued. If An Introduction to Mathematics was to be widely promoted, it would need some golden endorsement.

Qiu Huanian understood this logic and planned to think it over carefully later.

The two of them chatted over tea in Kuzhou Tower for a while when a servant from the Zhu household came in to report.

“What is it?” Su Xinbai asked.

The servant glanced at Qiu Huanian and quickly replied with clear articulation, “Replying to Young Madam, something has happened at the small school in the house. Since the Madam is out of the city worshipping Buddha and can’t return soon, we had no choice but to come and fetch you.”

The Zhu family’s small school was where Zhu Xian, Jiujiu, and Xin Yao attended.

Qiu Huanian frowned. “What happened?”

“I’m not entirely sure, just that a girl from the Zhu family’s relatives had an argument with Miss Xian, and Miss Du also got angry. It’s not a good look if word gets out, so we urgently need an elder to step in.”

As soon as Qiu Huanian heard that Jiujiu was involved, he couldn’t sit still.

Su Xinbai stood up. “Get the carriage ready. I’ll go back with Huanian.”

“It only takes a little more than a quarter of an hour by carriage from Kuzhou Tower to the Zhu residence. Don’t worry.”

Qiu Huanian nodded. He trusted that Jiujiu was smart enough not to suffer a loss, but every parent’s heart aches for their child—even a little grievance was hard to bear.

The carriage sped back to the Zhu residence. Someone had already run ahead to inform them, and the gatekeepers had removed the threshold from the side door, allowing the carriage to drive straight in and stop in front of the small school.

Su Xinbai got out and saw a young woman already standing by the school’s door, her brows slightly furrowed.

Dianmo went up to ask, “Second Young Madam, what are you doing here?”

The Zhu family hadn’t split into branches yet, so all the grandchildren shared the same seniority. The second son was the eldest of the second house and managed some of the Zhu family’s business, though he was far inferior to Zhu Jingcheng.

Given Su Xinbai’s status, no one in the Zhu family dared to slight him. The Second Young Madam tucked a strand of hair behind her ear and offered a graceful smile. “It’s good that Elder Sister-in-law is back. I heard my cousin Xia’er got into a dispute with Xian’er and the Young Lord’s daughter at school. I was worried, so I came to apologize.”

“……”

Su Xinbai frowned, feeling uncomfortable with her words.

Qiu Huanian looked at this Second Young Madam and understood immediately.

Regardless of the cause of the conflict or who started it, the Second Young Madam had first positioned herself as the weaker party, subtly implying that the main branch was using its power to bully others.

This Second Young Madam’s surname was Zhu, and her given name was Lou. Her family ran a silver shop, and her father was a close friend of the Zhu family’s second master. Years ago, they had arranged a match between their children.

The Xia’er she mentioned was her younger sister, Zhu Xia, twelve years old this year. As a relative of the Zhu family, she also studied at the small school.

A servant by Su Xinbai’s side quietly explained the connections to Qiu Huanian in a few words.

Zhu Xia? Qiu Huanian thought the name sounded familiar.

Su Xinbai didn’t understand Zhu Lu’s veiled words, but he knew something was off and didn’t want to listen any longer.

He directly walked into the small school building, and everyone quickly followed.

Qiu Huanian entered the three-room hall built by the water and immediately saw Jiujiu in the middle of the room.

Jiujiu was frowning and rubbing her wrist. Coral stood protectively beside her, and several differently dressed servants surrounded her, though none dared make a move.

Su Xinyao wasn’t at school today due to illness. Zhu Xian stood next to Jiujiu, her normally composed face now dark with conflicting emotions.

Facing them, a young girl stood a few steps away, crying into her handkerchief with soft sobs, looking so pitiful it tugged at the heartstrings.

Zhu Lu walked over and took the girl into her arms.

“Xia’er, don’t be afraid. Your sister is here.”

The girl looked up tearfully. Her delicate features bore a five-point resemblance to Zhu Lu, and a red slap mark adorned her cheek.

Judging by the expressions and positions of those in the room, it seemed Jiujiu had hit her.

Qiu Huanian frowned and walked over to Jiujiu’s side.

Jiujiu turned around and was startled to see Brother Hua. She quickly dropped her previously defiant stance and lowered her head.

Zhu Lu’s sharp eyes swept over Qiu Huanian before returning to her sister. “Xia’er, tell your sister what happened.”

“Don’t worry. Elder Sister-in-law is here. She comes from a noble family and is the fairest of all. If this really can’t be resolved, our matriarch will step in for us. Just speak freely.”

Zhu Xia sobbed a few more times, then hoarsely said with grievance, “Du Quehan… Du Quehan suddenly slapped me.”

With that, all eyes in the room fell on Jiujiu and Qiu Huanian.

Su Xinbai immediately sensed that something was wrong.

Even someone like him, who never concerned himself with household squabbles, understood how damaging it could be for an unmarried girl to be known for hitting others.

Min Leyi, the daughter of the dean of Qingfeng Academy, was still excluded from Liaoping’s elite social circle for fighting at a banquet over a kitten. She couldn’t even find a decent match.

Su Xinbai, trusting his instincts, quickly said, “Today’s matter stays within this room. No one is allowed to spread it.”

No sooner had he finished speaking than Zhu Lu began to cry and wail, “Elder Sister-in-law, what do you mean by that? Is my Xia’er just supposed to take the hit for nothing?”

Zhu Lu wept bitterly and began blaming herself sentence by sentence before Su Xinbai could respond.

“I know the Young Lord’s daughter is noble. We, as poor relatives, can’t compare. My sister suffering this kind of grievance is all because I, her elder sister, am incompetent. These past years, I’ve given birth and raised children for the Zhu family, accepted concubines for my husband—every contribution and sacrifice, I’ve made them all.”

Su Xinbai felt even more uncomfortable hearing this, like there was a thorn constantly pricking at him.

Su Yi had always been upright in office and never used his status to oppress the people. Su Xinbai himself was introverted and, despite his noble background, had never truly mistreated anyone in the Zhu household.

Yet now, from Zhu Lu’s tone, it sounded as if she had suffered immensely under Su Xinbai.

Her mentions of taking concubines and bearing children further irritated Su Xinbai without reason.

And worst of all, she framed it all as self-blame, leaving Su Xinbai speechless.

Su Xinbai, the scholarly and aloof beauty who couldn’t understand her insinuations, was one thing—but Qiu Huanian was a different story.

He chuckled, drawing everyone’s attention. Even the weeping Zhu sisters paused in surprise.

Qiu Huanian took Jiujiu’s hand, examined it carefully, and gently rubbed it. “Does it still hurt? Hitting such a thick-skinned person—what if you injured yourself?”

“Brother Hua?” Jiujiu froze.

She knew she had been impulsive and was prepared to be scolded by Brother Hua.

But instead of scolding, he had defended her and even spoken so harshly.

He didn’t give Zhu Lu, the Second Young Madam, any face at all.

“You—You—”

Zhu Lu hadn’t expected Qiu Huanian to speak so bluntly and was at a loss for words.

She didn’t dare truly fall out with a titled lord. She knew that if things escalated, the Zhu family would undoubtedly side with Qiu Huanian and Du Yunse. Her own maiden family, the Zhu family, was insignificant.

Qiu Huanian looked at her. “Does Second Young Madam have any business with me?”

Zhu Lu took a breath and forced herself to say, “The Young Lord’s daughter has a fiery temper. The Young Lord should discipline her properly. Today she slapped my sister—that’s a small matter—but what if something bigger happens in the future?”

“That’s not something the Second Young Madam needs to worry about. I’ve always taught my child to be clear about right and wrong, and to own up to her actions.”

Qiu Huanian patted Jiujiu’s head. “Jiujiu, tell brother what just happened?”

Qiu Huanian believed Jiujiu would never strike out without reason.

Jiujiu glanced at Zhu Xian, then at Su Xinbai, and shook her head at Qiu Huanian.

Qiu Huanian understood. “Xinbai, have everyone leave except for the children directly involved. This isn’t something suitable for everyone to hear.”

Zhu Lu clenched her palm. “What’s so unsuitable? Everyone else is a witness. Let’s all hear what happened.”

Su Xinbai ignored her and followed Qiu Huanian’s instructions directly.

With Su Xinbai present, no one paid Zhu Lu any attention, which made her eyes brim with tears in frustration.

After Su Xinbai dismissed the others, only he, the Zhu sisters, Zhu Xian, Qiu Huanian, Jiujiu, and their personal attendants remained in the small study hall.

Zhu Xian finally let out a breath of relief. Her tense nerves relaxed slightly, but her face still showed signs of distress.

With Qiu Huanian backing her, Jiujiu gained confidence and directly asked Zhu Xia, who was dabbing her eyes with a handkerchief, “Are you going to say it yourself, or should I say it for you?”

With the unrelated people gone, Zhu Xia and Zhu Lu’s arrogance diminished significantly.

Jiujiu spoke plainly, “Usually, Sister Xian, Xin Yao, and I sit together. Today Xin Yao didn’t come, so Zhu Xia sat with us. At first, we didn’t think much of it. But during the noon break, she suddenly pulled us aside and began gossiping.”

“Zhu Xia hinted repeatedly, asking about Sister Xian’s two older brothers. She also spoke of her own cousins, saying they were all talented and gentle.”

“She thought she was subtle, but everyone could understand her intent. Sister Xian didn’t want to engage, so she said that her younger brother wasn’t thinking about marriage yet and her older brother wouldn’t take concubines.”

“Zhu Xia was embarrassed after being seen through and got angry, sarcastically saying that Sister Xian, being a concubine-born daughter, was acting like a jealous wife who opposed men taking concubines.”

Zhu Xian, eyes reddened, tugged at Jiujiu’s sleeve. Jiujiu bit her lip.

Su Xinbai’s face darkened; he finally understood what had happened.

“No matter. Jiujiu, continue. There’s no one else here. You don’t need to spare my feelings.”

Jiujiu went on, “Those words insulted even Brother Xinbai. Sister Xian got angry but didn’t dare speak up, fearing people would gossip about Brother Xinbai behind his back.”

“I stood up for Sister Xian and argued with Zhu Xia. I said true love does exist in this world. Just because she hasn’t experienced or seen it, doesn’t mean there aren’t lovers who stay devoted to each other.”

“Zhu Xia didn’t argue with reason. She started saying nonsense, like how once my older brother becomes a high-ranking official, he’ll take ten or more concubines into his household, and then I’ll see if I still dare speak such shameless words.”

“She insulted me—I could argue back. But when she slandered my brother and tried to stir up discord between my brothers, I just…”

Jiujiu still remembered that only a year ago, she had been living in poverty in Dujia Village, rarely able to eat meat. It wasn’t until her brother returned and worked hand-in-hand with Huage (Qiu Huanian) that they turned the family’s fortunes around.

The love between Du Yunse and Qiu Huanian had been on display every day before Jiujiu’s eyes, becoming the best form of education and making her believe in love and devotion.

For Zhu Xia to speak so dismissively of it was to touch Jiujiu’s deepest sore spot.

So Zhu Xia ended up with a slap across her face that caught everyone off guard.

Before that, they had been speaking in low voices at their seats, and the others hadn’t heard the exact details.

It was only after Jiujiu struck her that people in the hall took notice. Since neither girl was willing to back down and Zhu Xian, as the host, was distraught and unsure how to resolve the conflict, none of the servants dared take sides. They rushed out to bring Su Xinbai back.

Su Xinbai’s cold gaze fell on Zhu Lu and Zhu Xia. Zhu Xia was already shaken. Zhu Lu still tried to keep her composure.

“Sister-in-law, children speak bluntly. Don’t take it to heart. Besides, Xia’er was only speaking the truth. She’s thinking of the Zhu family’s future. Big Brother is the eldest grandson and still childless. The Zhu family’s lineage is in danger.”

Zhu Lu knew that now her plans were exposed, she would surely offend Su Xinbai. But she also knew that since they planned to add a concubine to Zhu Jingcheng’s household, they’d eventually offend him anyway, so doing it sooner didn’t matter.

In this regard, she wasn’t afraid of Su Xinbai.

After all, Zhu Jingcheng’s childlessness had always been a sore point among the elders. As long as things didn’t escalate too much, if this matter reached the matriarch, Zhu Lu believed she wouldn’t be the one punished. The elders might even be pleased she had torn away the pretense.

As for her brother-in-law Zhu Jingcheng, Zhu Lu believed no man could endure being left without female companionship. Even her own husband took several maids and servants with him when traveling for business to “relieve his needs.” Zhu Jingcheng surely harbored frustration.

By then, she could simply propose bringing in her beautiful and youthful cousins. In a year or two, they’d bear children, and the Zhu family’s heirs would fall into her natal family’s hands. Wouldn’t that be perfect?

After all, she was a legitimate Zhu family wife, not a servant. What could Su Xinbai, a cold and aloof “golden Buddha,” possibly do to her?

Thinking this, Zhu Lu squeezed out a few more tears and shifted the tone.

“If sister-in-law is truly angry, we’re willing to accept punishment. Why not take us to the matriarch right now and clear everything up?”

Su Xinbai inhaled deeply, his hands slightly trembling, too enraged to speak.

Qiu Huanian shook his head and patted Su Xinbai.

After Su Xinbai opened his heart and began building a deep bond with Zhu Jingcheng, the household affairs he used to ignore started piling onto him.

Su Xinbai had always been a reclusive, scholarly beauty who paid no attention to worldly matters. In his natal family, his mother and later stepmother managed everything efficiently. He never had to worry.

Now, faced with someone like Zhu Lu, he found himself at a loss.

Qiu Huanian thought, This is the downside of large families with many wives and concubines. From now on, whether marrying into or marrying out, our family must set a rule—no concubines allowed.

And to achieve that, he and Du Yunse would have to work hard to elevate their status so they could protect their loved ones.

“If I’m not mistaken, Xinbai should be the Zhu family’s zongfu, right?”

Zongfu or zongfu-ren refers to the spouse of a family’s main heir—usually the eldest son or grandson. Regardless of how the family splits, they remain the main branch and have authority over all non-direct members of the household.

Su Xinbai paused for a moment before realizing Qiu Huanian was reminding him that he had full authority to punish Zhu Lu without taking her to the matriarch.

Zhu Lu opened her mouth, surprised by this turn.

Indeed, Su Xinbai was the Zhu family’s zongfu, but he had never involved himself in managing the household, and Zhu Lu had instinctively forgotten that. If not for Qiu Huanian’s reminder, Su Xinbai himself might not have remembered.

Su Xinbai exhaled coldly, “Send Miss Zhu Xia back to the Zhu household. She no longer needs to attend the study hall.”

“As for Second Sister-in-law, go to the ancestral hall and copy three volumes of scripture. You may come out only after finishing.”

…

It was Su Xinbai’s first time punishing anyone, and he was not harsh. Qiu Huanian didn’t say much. After all, Su Xinbai wasn’t Jiujiu—he didn’t need teaching.

Besides, Qiu Huanian believed that once Zhu Jingcheng returned and learned of all this, he would not let anyone who upset Su Xinbai off easily.

The two were complementary—sharp and capable Zhu Jingcheng protected Su Xinbai in a complicated environment, and the pure, brilliant Su Xinbai fulfilled all of Zhu Jingcheng’s scholarly dreams.

Dian Mo took Su Xinbai’s orders and led a few old women and servants to escort Zhu Lu and Zhu Xia away.

Su Xinbai invited Qiu Huanian to stay for dinner. Qiu Huanian shook his head. “Go rest. The study hall can’t carry on today. I’ll take Jiujiu home first.”

Jin San was waiting with the carriage outside the Zhu residence. Qiu Huanian got in with Jiujiu and Coral.

Jiujiu leaned listlessly against Qiu Huanian, lost in thought.

Qiu Huanian instructed Jin San, “Don’t go home yet. Head to the Shu residence in Sweetwater Alley.”

“Huage, why are we going to the Shu family?”

“To deliver a book to your sister Rutang. The sample copy of Essentials of Mathematics: Equations is ready. I promised to give her one once it was printed.”

Jiujiu perked up, eagerly flipping through the book. “Huage, I want one too.”

“Once Qimin Bookstore finishes printing, you’ll definitely have one.”

Seeing her mood improve, Qiu Huanian smiled and patted her head. “What were you thinking about just now, Jiujiu?”

“I was just thinking… if even someone like Brother Xinbai, with his high status and scholarly excellence, can be angered and manipulated by Zhu Xia’s sister, then I…”

Jiujiu hugged Qiu Huanian’s waist, burying her fluffy head into his embrace, seeking comfort.

In ancient times, people married young. Jiujiu already knew some were asking her brothers about potential marriage. Though they wouldn’t agree to any engagement this early, she still had worries.

Qiu Huanian gently patted her back. “Our Jiujiu is a good girl. You’ll definitely find a good match. Your brothers will help you choose carefully. And if things don’t work out, we’ll just recruit a husband into our family—then you won’t have to fear being mistreated.”

Jiujiu’s face turned bright red. “Huage, don’t joke around. I have brothers and cousins. How could I recruit a husband? That’d ruin our family’s reputation.”

Qiu Huanian flicked her nose.

“What does reputation matter? Let your brother work hard. Maybe someday people will be lining up to become a son-in-law to the Du family. You’ll walk outside and have men volunteering to be recruited.”

“Huage!” Jiujiu shouted in embarrassment.

They joked for a while until Jin San drove the carriage to Sweetwater Alley. Qiu Huanian lifted the curtain, then let it fall again.

“Huage, what’s wrong?”

Jiujiu lifted a corner of the curtain and looked in the direction Qiu Huanian had just peered.

Coincidentally, she saw Zhu Xia, who was supposed to be sent home in the Zhu family’s carriage.

Jiujiu realized Huage didn’t want to deal with unpleasant matters and had dropped the curtain. She lowered her voice and asked, “Does Zhu Xia live in Sweetwater Alley too?”

Qiu Huanian nodded. He finally remembered why Zhu Xia’s name had sounded familiar.

During last year’s provincial exams, he and Du Yunse had borrowed lodging at the Shu residence, and Rutang had once told him about her parents’ concerns.

She had mentioned having a friend named Zhu Xia whose father also ran a jewelry shop. Though the legal wife had both sons and daughters, the man kept taking concubines. When Rutang tried to console Zhu Xia, Zhu Xia snapped at her, saying her own father had no sons and Rutang should persuade her mother to let him take concubines.

Rutang had been furious and never spoke to Zhu Xia again.

Now it seemed that Zhu Xia then was the same Zhu Xia now.

Qiu Huanian told Jiujiu the backstory. Jiujiu gritted her teeth. “So Zhu Xia has always been like this. She just hid it well before—I didn’t notice at all.”

Qiu Huanian sighed. “Zhu Jingcheng and Zhu Jingwei won’t let the Zhu family have their way. Let them waste their efforts.”

Once Zhu Xia was out of sight, Qiu Huanian told Jin San to move the carriage forward, and he got out with Jiujiu and Coral.