Chapter 4

"Right...," Wu Ji, drenched in sweat, finally said dejectedly. Today's goal was unattainable; how could this person calculate so quickly! He was filled with amazement. In his view, the problem was so complicated that no one could solve it quickly, and Cai Yong was a good example of this.

Zhang Xun, greatly relieved, laughed and said, "Hehehe... Brother Bojie truly lives up to the admiration of all scholars. If the people in your household have such knowledge, the younger generation will surely feel inferior."

Wu Ji, hearing this, blushed with shame and said urgently, "Qin Zijin, how did you calculate it? You, you didn't even need to work it out step by step?"

"Hmph, this is a mental arithmetic technique passed down to me by my lord. How can I tell you?" Qin Feng laughed.

Cai Yong, hearing this, felt a bit awkward. He knew that Qin Feng was speaking on his behalf. Scholars valued their reputations, and he was grateful for Qin Feng's support.

"This...," Wu Ji was no longer as composed as before, standing in the hall, unsure whether to advance or retreat. "Lord Cai is renowned throughout the land, and even the servants in his household are so capable. I will take my leave!" Wu Ji said a few polite words and wanted to slip away.

"Wait, it is impolite to come and not return the favor. I have a problem for you to solve," Qin Feng called out to him.

Wu Ji's expression was mixed. He was proud of his talent and unwilling to give up. If he could solve the problem, it would be a way to regain his dignity. If the news spread, it would be good for his reputation. He calmed himself and said, "Please, teach me..."

Cai Yong, hearing this, remained calm and waited for Qin Feng to pose the question, wanting to see if he was truly talented. There was no need to elaborate on Lu Zhi and others, who felt the same way. Cai Yong was not just putting on a show; Qin Feng had answered the question so quickly that he must be a person of great talent. They all wanted to hear what kind of question he would ask.

Qin Feng, unexpectedly getting a chance to show off on his first day at Cai's residence, smiled confidently and said, "I'll give you a simple one. Assume Luoyang has 100,000 households, each with five people, and each person consumes one sheng of rice per day. How much rice will these 100,000 households consume in three days?"

"Ah! This...," Wu Ji was immediately dumbfounded. He had some idea of how to calculate it, but without any tools, how could he do it?

Cai Yong, stroking his long beard, smiled and instructed, "Go, give him paper and pen."

Wu Ji was now trembling with fear. The problem seemed easy at first, but it was no less difficult than the one he had posed. It had taken him two days to solve the previous problem... He had no choice but to pick up the pen and start calculating on the paper.

"Damn you," Qin Feng scolded sternly, "go and calculate slowly. Don't dirty the eyes of the gentlemen here." For such a simple multiplication problem, Qin Feng could only chuckle at the ancient people's level of calculation...

Wu Ji, ashamed, hurriedly left.

Cai Yong and the others looked at Qin Feng with shining eyes, making him feel uneasy. He quickly said, "I will take my leave."

Cai Yong, a great scholar of the Eastern Han, could not let Qin Feng leave so easily after seeing his extraordinary skills. "Wait, Zijin, do you have the answer to your question?"

Lu Zhi and others were also waiting for Qin Feng's answer.

"100,000 households, each with five people, is 500,000 people. One person consumes one sheng of rice per day, so 500,000 people consume 500,000 sheng of rice per day. In three days, they will consume 1,500,000 sheng. It's much simpler than the previous problem," Qin Feng laughed.

Much simpler! Cai Yong and the others looked at each other in surprise. To them, both problems were of the same level, with large numbers and complex calculations.

"How did you calculate it so quickly!" Cai Yong stood up in shock.

Damn, it's been a thousand years, and this is a great opportunity to show off. Qin Feng thought that this reputation would spread, which would be beneficial for his future success. He came to Cai's residence to work because Cai was a leading figure in the academic world, and there were many opportunities. Of course, Cai Yan was also an important reason. He boldly walked over, picked up the paper and pen, and quickly wrote down the solution.

Ma Riji and others walked over and saw a series of unfamiliar symbols.

"What is this?" Lu Zhi couldn't help but ask.

Qin Feng, seeing the scholars' puzzled looks, laughed and said, "Arabic numerals." When he was in school, his math teacher had mentioned that Arabic numerals appeared around 500 AD. These Han people wouldn't understand, and even the Arabs probably wouldn't.

"Arabic numerals!" Cai Yong and the others looked at each other in amazement.

Qin Feng, seeing the scholars' stunned expressions, couldn't help but feel a bit smug. After all, he was the only one on Earth who understood them! Seeing their amazed looks, his confidence grew. With knowledge nearly two thousand years ahead, it would be hard not to stand out.

"Arabic numerals?" Cai Yong, stroking his white beard, asked in confusion.

Qin Feng thought for a moment and added Chinese characters next to each number. He then wrote down the multiplication table, from "one times one is one" to "nine times nine is eighty-one."

Cai Yong and the others looked at Qin Feng as if he were a monster, beginning to understand some of the subtle connections.

"Brother Bojie, if these Arabic numerals spread, the field of mathematics will change...!" Zhang Xun, realizing the implications, exclaimed.

"Zijin, is this your creation?" Ma Riji asked urgently.

"Just a thought, a discovery, and a learning," Qin Feng laughed.

In the Han Dynasty, scholars had already recognized the importance of mathematics, which was already a recognized discipline. People like Cai Yong were involved in it. They quickly understood the significance of Arabic numerals for mathematics.

To put it simply, in the Eastern Han, calculations were done using square characters on bamboo strips, which required tons of bamboo for large numbers. The complexity of using square characters on bamboo strips was unimaginable. Qin Feng's Arabic numerals were much simpler and significantly more important for mathematics.

Innovations and changes in a field could be achieved by ordinary people. In the eyes of scholars like Cai Yong, Qin Feng's talent was undeniable and exceptional!

Lu Zhi's eyes sparkled. In the military, mathematics was crucial for troop deployment, logistics, and equipment. He knew that it took a whole day and several large boxes of bamboo strips to calculate the monthly food consumption for a camp of soldiers.

It was a waste of talent for someone like Qin Feng to be stuck in Cai's household. Lu Zhi, thinking about this, quickly said, "Brother Bojie, would you consider letting me take Zijin back to my residence?"

The cunning officials, Yang Biao and others, thought that this old fox had taken the lead. They all knew that attracting talented people was essential for the prosperity of their families.

What's going on! This old man wants to take me away! Qin Feng knew that if he followed Lu Zhi, he would have a better future during the Yellow Turban Rebellion than with Cai Yong.

Lu Zhi was a military official. Although he was later falsely accused of military failure and sent back to the capital, he was quickly released and appointed to a high position like Minister of Works. If he could help Lu Zhi through the prison ordeal during the Yellow Turban Rebellion and earn some military achievements, he could surely become a significant official.

However, Qin Feng also thought that if he left, he would miss the chance to meet Cai Yan, a famous scholar of the Three Kingdoms, who was right there! Besides, changing positions would not look good. In the Cai family, Cai Yong would be his father-in-law, so it wouldn't be a problem.

Cai Yong, seeing Lu Zhi openly trying to poach his talent, frowned. He couldn't refuse outright due to politeness and looked anxiously at Qin Feng.

Qin Feng, feeling uneasy under the scholars' gaze, quickly declared his loyalty, "Thank you, General Lu, for your kind offer, but Qin Feng is already here and will not leave easily." He thought to himself that he needed to get to the inner chambers to meet Cai Yan. Admiring a talented woman was one thing, but if she was also beautiful, it would be... hehe...

Cai Yong, not knowing Qin Feng's secret plans, would have chased him away with a stick if he knew. Hearing Qin Feng's words, he was pleased and said, "It seems Brother Zigan will be disappointed."

Seeing Qin Feng's refusal, Lu Zhi sighed, and the matter was dropped. Unlike opportunistic officials, they valued talent and included Qin Feng in the banquet.

Qin Feng explained in detail the application of Arabic numerals and the multiplication table. Cai Yong and the others, hearing the subtleties, clapped in admiration, further appreciating his mathematical talent.

Jiang Chuan and others, seeing Qin Feng become the center of attention at the banquet, were dumbfounded, envious, and resentful. The maids, like Xiao Hong, admired his eloquence.

After Yang Biao, Lu Zhi, and Ma Riji left, the conversation among the prominent families in Luoyang included a bit about Qin Feng.

...

"Zijin, I didn't expect you to have such great talent in mathematics," Cai Yong, holding the multiplication table written in Arabic numerals, said lovingly, leading Qin Feng to his study.

"Sir, you flatter me," Qin Feng said. He was not used to calling others "lord" and used this term instead.

Cai Yong was not bothered by this. Talented people should be used in the right place. He thought the same as Lu Zhi and others and smiled, "Cai Lin, is there a vacancy in the accounting department?"

"Lord, the manager Zhang has left due to illness, and we are short of a manager," Cai Lin said.

"Oh, that's convenient. Zijin has great talent in mathematics. From now on, he will manage the household accounts," Cai Yong said.

"Yes, Lord," Cai Lin was also amazed. He had not misjudged Qin Zijin, who was not an ordinary person. Others might work for years without promotion, but he had become a first-class manager on his first day. It would shock people to hear this.

"You may leave," Cai Yong said.

A first-class manager, so I can go to the inner chambers openly! Qin Feng, secretly delighted, imitated Cai Lin's gesture and bowed, "I will take my leave," and walked out.

"Father, I heard you obtained a new method of mathematics!"

Just as Qin Feng was about to leave, a voice like a silver bell came from outside.

What a beautiful voice, I must see who the owner is! Hearing the call to "Father," could it be the famous scholar Cai Yan? Qin Feng slowed his steps, hoping to meet the person.