APSIL -Chapter 40 Has the Master and Disciple Fallen Out?

If there was one word to describe the young dandies of Cuiyun Retreat, especially Zhang Chen and Lu Sanlang, it would be complicated.

Earlier, at Zhang Manor, even when Tang Ming and Xie Wanquan had accused Zhang Shou of fraud and deception, Zhang Chen and Lu Sanlang had still believed Zhang Shou couldn’t possibly be the mysterious “Old Master.” His build, his voice, even the way he carried himself were completely different from the teacher who had instructed them before.

Then Ge Yong had suddenly appeared.

For a brief moment, they had even wondered excitedly whether they had unknowingly become disciples of the legendary Imperial Tutor all along, and whether last night’s lesson had simply been one of the old man’s elaborate games.

But after all the twists and turns…

No matter who that “Old Master” had really been last night, one thing was certain—

Ge Yong had dumped them all onto Zhang Shou.

Now, with Zhang Chen and Lu Sanlang taking the lead, the entire group sat obediently inside Qingfeng Xulai Hall, staring eagerly at Ge Yong and Zhang Shou, who sat opposite each other across a small square table.

The two were discussing mathematical concepts that sounded like heavenly scripture to everyone else.

Ge Yong spoke of the method of polygon approximation, of “three, four, five” right triangles.

Zhang Shou responded with infinite series, iterative methods…

Then the conversation reached Arabic numerals.

After only a few exchanges, Ge Yong’s face darkened.

He abruptly shot to his feet.

“Those barbarian scribbles from overseas…”

“…how can they possibly compare to counting rods?”

The moment those words were spoken, every young noble present perked up.

Could it be—

Had master and disciple acknowledged one another only moments ago…

…just to fall out immediately afterward?

If so…perhaps now they could finally settle old scores!

Unfortunately for them, events took a completely unexpected turn.

Ge Yong strode forward, grabbed Zhang Shou by the sleeve, and hauled him to his feet.

Without sparing the pitiful students a single glance, he dragged Zhang Shou straight out of the hall.

Lu Sanlang, daring to glance back, even saw Zhu Ying hurriedly trying to follow after them.

Ge Yong immediately glared at her.

“I’m discussing mathematics with this brat. Don’t come tagging along, Xiaoying! I discovered when you were seven or eight years old that you have absolutely no talent for mathematics!”

Zhu Ying looked ready to protest.

Zhang Shou smiled reassuringly.

“It’s fine. It’s only a discussion about numbers.”

Truthfully, when Zhang Shou had first discovered after arriving in this world that Arabic numerals, which had only become widespread in Chinese history centuries later, had already been officially promoted throughout the empire during the dynasty’s early years…

…he had been pleasantly shocked.

Counting rods were indeed an ingenious ancient invention.

But Arabic numerals, originating from India and eventually conquering the entire world—even replacing the once-dominant Roman numerals—had become the universal language of mathematics for a reason.

That wasn’t mere coincidence.

Yet despite the empire’s gradual acceptance of Arabic numerals…there were still die-hard traditionalists.

Such as the old man standing before him.

Ge Yong was an unwavering supporter of counting rods.

Zhang Shou truly hadn’t expected that.

After leaving Qingfeng Xulai Hall, Zhang Shou gave Qi Liang a meaningful look, signaling him to help Zhu Ying keep things under control.

Then, instead of allowing Ge Yong to continue dragging him, he turned the tables and led the old man toward Rippleless Waters Pavilion.

Without saying a word, he took paper and brush from the bookshelf.

He spread them on the table.

Then he began writing.

What he wrote wasn’t some profound theorem.

Nor was it an especially difficult problem.

It was…the long-division method of extracting square roots.

To people of later generations, finding a square root required nothing more than pressing a button on a calculator.

But now…

Using brush and ink, Zhang Shou carefully laid out the entire calculation process.

Thanks to his excellent mental arithmetic, only a few minutes later he had completed the decimal expansion of √10.

Immediately afterward, he solved the same problem again—using a much faster iterative method.

When he finally placed the two identical answers before Ge Yong…the old man’s face looked as though frost had settled upon it.

“The first method uses more paper,” Zhang Shou explained calmly.

“But it has one major advantage.”

“If your counting rods are accidentally disturbed, you have to begin all over again. They also require a large number of rods, and mistakes are difficult to trace.”

“This written method, while cumbersome, records every step clearly. As long as you understand the procedure, anyone can verify the calculation.”

“The second method is much faster.”

“It only requires a little more effort when making the initial estimate.”

“And these numerals from overseas…”

“…they’re simple.”

“…easy to learn.”

He knew exactly what troubled Ge Yong.

It was much like those who insisted that traditional characters were inherently superior and condemned simplified characters without exception.

Arabic numerals were, after all, completely foreign.

“Master.”

“When Zu Chongzhi created the Daming Calendar, many opposed him.”

“They claimed the ancient calendar systems were sacred and eternal.”

“But what did Zu Chongzhi say?”

“We should not blindly revere the ancients while doubting the present.”

“If something from antiquity is incorrect, and we stubbornly continue using it…”

“…wouldn’t that simply mean making the same mistake over and over?”

“Mathematics is no different from astronomy.”

“It has to advance with the times.”

After speaking, Zhang Shou rose, fetched a still-warm teapot from a woven basket, rinsed a teacup, poured tea, and respectfully offered it to Ge Yong.

Then he smiled sincerely.

“I only became interested in mathematics after reading the books you left behind.”

“Later, a traveling peddler happened to bring several secondhand books from overseas.”

“When I saw these numerals, which were even simpler than counting rods, I became fascinated.”

“You’ve already seen Qi Liang’s workbook.”

“All the problems were written using these numerals.”

“If you believe this is heresy…”

“…then I’ll admit I was wrong.”

Fortunately…when Qingfeng Xulai Hall had been renovated, Zhang Shou himself had sorted through everything inside.

No one knew the books Ge Yong had left behind had long since crumbled into useless scraps after the oilcloth wrapping was removed.

Otherwise…he would have had an even harder time explaining himself.

“‘You’ll admit you’re wrong…’

“‘…but you won’t change your mind.'”

“So that’s your attitude?”

Ge Yong stared at him.

Seeing Zhang Shou nod calmly…the old man remained silent for a long while.

Finally…he chuckled.

“If you’d been this stubborn back when I was living here in seclusion…”

“I’d have scolded you thoroughly and stormed off.”

“But…”

“…who told you to master mathematics so quickly?”

“And even produce students like Deng Xiaodai and Qi Liang…”

“…both talented and hardworking?”

He sighed.

“I know.”

“These past years, I’ve insisted on using counting rods.”

“I’ve always claimed I was preserving tradition…”

“…when in truth…”

“…I’ve simply become stubborn.”

“Even the few old friends who truly understand mathematics…”

“…have all switched to those overseas numerals.”

“They’ve merely been too polite to say it to my face.”

Then he glared fiercely.

“And you…”

“…have absolutely no respect for your teacher!”

Zhang Shou immediately apologized with an ingratiating smile.

Only then did Ge Yong’s expression soften.

“Your future father-in-law didn’t ask me to teach you mathematics.”

“The Ten Mathematical Classics were only included among those books because you irritated me.”

“But according to Xiaodai, you’ve also studied the classics.”

“You remember everything you read.”

“Such talent shouldn’t be wasted on trivial matters.”

Fearing Zhang Shou might pretend not to understand, Ge Yong added emphatically, “If you’re greedy for good food, tell someone else how to cook it.”

“Don’t waste your own time standing in the kitchen.”

“That time would be better spent studying mathematics.”

“If you could push Zu Chongzhi’s calculation of π just one step further…”

“…I could die without regrets.”

“For over a thousand years…”

“…no one has advanced it even a single step.”

“Even his Zhui Shu has been lost.”

Zhang Shou hurriedly lowered his head, respectfully agreeing while hiding the subtle change in his expression.

Mathematics was a vast field.

Compared with the countless unsolved conjectures of modern times…calculating π was little more than asking a supercomputer to run for a while.

But telling the truth wouldn’t help.

Even if Ge Yong believed him…the old man would probably cough up blood from shock.

Perhaps later…he could simply “discover” fragments of lost mathematical works like the Zhui Shu, adapting a few concepts from modern textbooks.

It might even give the old scholar a new lease on life.

The very next moment, however, Ge Yong abruptly changed the subject.

“Tang Ming and Xie Wanquan were obviously sent here by someone.”

“Though I’ve long since retired…”

“…my identity still carries too many complications.”

“I can’t stay here for long.”

“I can protect you for today.”

“But after that…”

“…you and Xiaoying will have to deal with things yourselves.”

“Don’t blame your future father-in-law for leaving you and your mother in the countryside.”

“One day…”

“…you’ll understand.”

He paused before adding, “Treat Xiaoying well.”

“She may have been spoiled by her father…”

“…but her heart is good.”

“It’s rare that she truly likes someone.”

“Besides, her grandmother is firmly on her side.”

“Don’t let her down.”

Then the old man waved his sleeve.

“Come.”

“Let’s go back to Qingfeng Xulai Hall.”

“I ought to teach those youngsters a proper lesson.”

“After all…”

“…I can’t let the title of their grandmaster be just for show.”