Chapter 47
Chapter 47
For an hour, Xu Wensu wracked his brain, marshaling everything he had ever learned to create ten problems. They grew progressively more difficult. Xu Wensu was certain that not a single student present could solve even one of them. In fact, he was confident that few in the entire Xuanwu Prefecture could solve even a single problem.
And even if someone managed to solve one, that would be their limit. The later problems were terrifyingly difficult. Some he had taken from ancient mathematical texts, so ordinary people would not only be unable to solve them but would struggle to even recognize them. If a learned-but-untalented person like Shen Lang managed to solve even one, it would be an unprecedented event. Imagining himself lashing Shen Lang, Xu Wensu placed the test paper in front of him and said.
“Remember, if you get just three questions right, I will not pursue this matter further. But if you fail to get three right, you will receive thirty lashes with a whip. If you fail to solve a single one, you will receive one hundred lashes. I will teach you how to respect your teachers and your studies, and what the way of mathematics truly is.”
In his heart, Xu Wensu cursed Shen Lang.
‘Young man, you can’t get your way with everything just because you’re handsome. How dare you act so callowly while confronting me… In a moment, I’ll have you beaten half to death.’
Of course, Xu Wensu didn’t mention the full terms of their agreement. If Shen Lang answered five or more questions correctly, it would prove that Xu Wensu had been picking a fight, and he would have to apologize to Shen Lang in front of everyone. But could such a thing happen? It was as likely as the sun rising in the west, so there was no need to even mention it.
“Remember, you must finish within the hour. When the time is up, it’s over!”
After saying that, Xu Wensu personally lit an incense stick. It was one that would burn for exactly an hour.
Watching the scene, the Count shook his head in pity.
‘Shen Lang will be punished shortly!’
Even in his youth, Xu Wensu had lacked magnanimity and possessed a fiercely competitive spirit. However, to be a successful master, the most important thing was to use talent well, and the key was to appoint talented people to suitable positions. To let each person fully display their talents and let every object serve its purpose. The Count had always thought he had done so successfully, but seeing the situation before him, he felt truly regretful.
The man on his left was his live-in son-in-law. Though disobedient, and though there was a clear generation gap between them, the Count inwardly liked and was fond of Shen Lang. The man on his right was his confidant, who had managed the estate’s finances for over twenty years and on whom he relied heavily. So even though he was the master, it was difficult for him to command the man as he pleased.
For the dozen or so young men in the classroom, this situation was a completely amusing spectacle. Shen Lang had provoked the strictest and most frightening teacher, Xu Wensu… It was a rare event, one you wouldn't see once in ten years, and they were so excited they could hardly contain themselves. They were incredibly eager to see what would happen. Although they secretly wanted to see Teacher Xu Wensu humiliated, they wanted to see Shen Lang receive a hundred lashes even more.
‘Who told you to marry our goddess? Wouldn’t it be fun for all of us if you got a sound thrashing?’
***
When Shen Lang took the ten problems, a quiet sigh escaped him.
‘Good heavens! I wondered how hard the problems Xu Wensu spent an hour agonizing over could be, but they're this simple?! Let me, a proud master's degree holder and a doctor from the pinnacle of the sciences, solve them for you. This is a complete piece of cake!’
He looked at the first problem.
The first person has one grain of rice, the second has two grains, and the third has three. There are one hundred people in total. How many grains of rice do all one hundred people have?
Wasn’t this a fourth-grade? No, a fifth-grade math problem? As Shen Lang wrote the answer, he honestly felt like an imbecile for solving such a simple question. Of course, to Shen Lang, this problem was so simple it was embarrassing to even look at it properly, but for the people of this world, it was difficult enough. At the very least, among the dozen or so students in the classroom, not a single one could solve it in a short amount of time.
Shen Lang continued to the second problem.
‘Oh? This one’s a little interesting!’
To Shen Lang, it was a very simple problem, but to the people of this world, it was very difficult.
There is an unknown number of items. When counted in groups of three, two are left over. When counted in groups of five, three are left over. When counted in groups of seven, two are left over. The total does not exceed one hundred. How many items are there in total?
This could be solved with an equation. In less than three seconds, Shen Lang knew the answer was 23, without needing a computer. The third problem was even more interesting.
Three companions journey, their ages seventy,
Five plum trees blossom, with twenty-one branches.
Seven brothers reunite when the moon is full,
Divide by one hundred and five, and the truth you shall pull.
Did he think writing it as a poem would hide the true face of this simple math problem? Shen Lang still wrote down the answer without any effort. He continued to the fourth, fifth, sixth… all the way to the ninth problem. There wasn't a single question that could challenge him. He solved each one in under two minutes. And so, he pinned all his hopes on the final, ultimate boss problem.
The last problem took up a full page. As Shen Lang looked at it, his eyes widened in spite of himself.
‘This problem is interesting, and it has some difficulty! In fact, it’s quite hard?’
There are twenty trees in total. If you plant them in rows of four, what is the maximum number of rows you can make? Draw a diagram of the planting method. If it is less than fourteen rows, the answer is incorrect.
This problem looked simple, but it was one of the most difficult math problems on Earth. The average person would answer that planting 20 trees in rows of 4 would make 5 rows. Of course, that wasn't the correct answer. Because if you planted the trees in an irregular pattern, you could make more than 5 rows.
In the 16th century, a Roman completed a 16-row arrangement, and in the 18th century, the renowned mathematician Gauss created an 18-row arrangement. It wasn't until the 20th century that two masters of computer Go used a computer to create a 20-row arrangement, and in the 21st century, a new record that overturned this was born. Exactly 23 rows!
This was the problem Xu Wensu was most confident in. He had discovered this problem in an ancient mathematical text and had spent over ten years on it alone to create a 14-row arrangement. He didn't just stop at solving it; he enjoyed stumping people with it. His colleagues at the Count's estate, the Count himself, and even newly-minted scholars who had just passed their examinations were all perplexed by this problem. This was because no one's expertise in mathematics reached his level. When he drew the 14-row arrangement, everyone was astonished and looked at him with wonder.
He now brought out this problem as his secret weapon to test Shen Lang. He never thought for a moment that Shen Lang could solve it. He was just using it for show, to demonstrate to a country bumpkin like Shen Lang just how formidable he was. After all, Xu Wensu considered his own creation of the 14-row arrangement to be a truly great feat.
However, to Shen Lang, a 14-row arrangement hadn't even reached the level of 16th-century mathematics. He easily drew the 23-row arrangement, a solution that would appear thousands of years after Xu Wensu's answer. To be able to plant 20 trees in rows of 4 and make 23 rows—this was an earth-shattering level of achievement, a level that completely crushed the 14 rows Xu Wensu had created! Xu Wensu would probably be scared out of his wits if he saw this!
Shen Lang took less than ten minutes to solve the first nine problems, but he spent about thirty minutes on the last one. Of course, the computer produced the solution very quickly, spitting out the most brilliant answer in an instant. However, the answer was a very precise geometric figure, and not a single point could be drawn incorrectly, so transferring it to paper required a certain amount of time.
Even with time to spare, he continued to draw and write, preparing a contingency. To avoid putting pressure on him as he solved the problems, neither the Count nor Old Master Lin watched from his side. Xu Wensu sat at the head of the class, watching Shen Lang work, feeling inwardly triumphant. He had been watching Shen Lang the whole time and saw that he spent very little time on the first nine problems and most of his time on the last one.
This seemed like very normal behavior. In his view, the first nine problems had fixed answers; you either knew them or you didn't. Shen Lang surely wouldn't know the answers even if he tore his hair out, so he must have quickly glanced at them and then written down random answers. But the last problem, though the most difficult, was open-ended.
There are twenty trees in total. If you plant them in rows of four, what is the maximum number of rows you can make?
Anyone who saw this problem would feel a glimmer of hope and would start frantically drawing out solutions, constantly coming up with various answers. Eventually, they would realize that they couldn't produce a solution even after wasting months. Xu Wensu had taken over ten years to create his 14-row arrangement. Therefore, he was certain that Shen Lang would not be able to solve this problem.
‘A hundred lashes are already guaranteed.’
What made Xu Wensu so confident was Shen Lang's attitude. When solving the first nine problems, Shen Lang showed no calculation process and didn't use counting rods. In this era, no one performed calculations without using counting rods; even a master of mathematics would need to calculate for a long time with them to solve a problem. Not using them proved that he knew nothing and was just writing down random numbers. Not only Xu Wensu, but the Count also thought the same.
When the Count saw that Shen Lang never once used the counting rods, he began to worry that he might not be able to solve the problems. Was he supposed to just stand by and watch Shen Lang receive a hundred lashes? The boy had such fair and delicate skin, and Xu Wensu would surely not hold back. What if he was seriously injured? So, the Count quickly gave a signal with his eyes. In an instant, a servant outside the door rushed off to report the situation to the Countess.
If Xu Wensu were about to whip Shen Lang, it would be difficult for the Count to intervene, but the Countess could surely persuade him gently. After solving all ten problems, Shen Lang could have turned in his paper, but he deliberately held back, continuing to write and draw something. For the last few minutes, he stared blankly at the test paper.
Seeing this, Xu Wensu felt even more gratified.
‘You wet-behind-the-ears brat, you could stare at it for ten years and you still wouldn’t solve the problems I set. You arrogant fool, how dare you challenge me? Just wait. I’ll beat you to death for blocking my path and stealing my nephew’s good fortune.’
Because of the wind, the incense stick burned out in less than an hour. Xu Wensu said coldly.
“Time’s up. Hand in your paper!”
After saying that, he immediately walked over and snatched the paper from Shen Lang's desk. Xu Wensu said flatly.
“A learned-but-untalented fool who doesn’t even pay attention in class and only learns to spout nonsense. Ignorance truly breeds courage…”
He looked at Shen Lang’s answer sheet. Xu Wensu glanced at the first problem and instinctively started to draw a large X over it, intending to move on to the next one. But he froze mid-motion and his eyes returned to the first problem.
‘How… It’s correct? Is this possible?’
The first problem was simple, but it was more difficult than what he had taught in this class. Someone who didn't know advanced mathematics would have no choice but to add the numbers one by one, and adding up to one hundred would take until the incense burned out. Yet Shen Lang had solved the problem using the most precise method.
He looked at the second problem; it was also correct. The third was correct as well. From that moment, the color of Xu Wensu's face began to change in an instant. The fourth and fifth problems were also correct. In fact, Shen Lang's methods were of a higher level and more precise than Xu Wensu's, to a degree that couldn't be more perfect. A cold sweat broke out on Xu Wensu's back.
He himself had said that if Shen Lang got five problems right, he would apologize to him in front of everyone. Now that Shen Lang had gotten all five right, what was he to do? Xu Wensu then looked at the sixth, seventh, eighth, and ninth problems. He wasn't just breaking out in a cold sweat; he was utterly horrified.
‘I-Impossible! This is a ghost, it must be the work of a ghost!’