The Jingshi is still the same Jingshi, the only difference is that it is warmer than a few days ago, the spring flowers are blooming, and the wind is intoxicating.

A banquet was held in the Gao Gong Mansion as a welcome to Gao Guoyan and others, and to wash the dust for them. In the inner hall, in addition to Gao Gong, Mrs. Gao Zhang also attended as an elder, but she actually just came forward to say a few kind words, and then left the table in advance, after all, among the few people who came this time, only Gao Guoyan is the younger generation of the Gao family, and the rest of the people, regardless of their age, are just people in the family, Gao Gong stayed to eat with them, which is equivalent to the gift of the male host to the subordinate, and it is not suitable for her to stay at the table as the hostess.

After Mrs. Gao left, everyone began to eat. Because of the high arch, everyone didn't dare not talk about etiquette, and it was not allowed to talk while eating, so they had to eat silently. However, Gao Gong, as an elder, said a few words of persuasion to Gao Guoyan.

After finishing the meal, it was time to chat. After the next person withdrew from the table, Gao Gong first asked Gao Guoyan about his father's situation, and after hearing Gao Guoyan say that his father had said that he was about to ask for Zhishi, Gao Gong seemed to be a little distracted.

Gao Guoyan and Gao Shishi's brothers glanced at each other, but neither of them spoke to disturb his thoughts.

After a while, I heard Gao Gong sigh slightly: "People, you will always get old, I just hope that after getting old, I will look back on my life in my spare time, and I won't feel that I have missed too many opportunities, and I won't leave too many regrets, so this life is enough." ”

Gao Guoyan was not familiar with his third uncle, and he didn't dare to talk when he heard this, so Gao Pragmatic was different, so he immediately smiled and persuaded: "Third uncle, you have grasped the opportunity now, if you want to leave no regrets, now is the right time." ”

Gao Gong was stunned for a moment, and then showed a smile: "Yes, you have a point, but the third uncle, I am old, Yi Sheng ......sighed with emotion" He paused slightly, and suddenly stood up: "I am also close to Jiazi, I don't know how much time I have to serve Daming and His Majesty loyally, pragmatic, you and Guoyan are your own brothers, you and Guoyan are your own brothers, you talk slowly." ”

Gao Guoyan didn't say anything, even Gao Pragmatic didn't expect Gao Gong to suddenly have such a big emotion because of his second brother's imminent death, it seemed that he was afraid that he would be more focused on official affairs than before, and he couldn't help but be a little stunned, but he couldn't persuade him anything, so he had to say: "Third uncle, although things have to be done, you must also take care of your body, after all, your body is a revolution...... No, I mean, the body is the capital of innovation, if you are too busy, if something happens to the body, then it is really a big mistake! ”

Gao Gong laughed, waved his hand and said: "I know my body, I probably won't be able to die in the past few years, you are young, don't worry about these things...... By the way, I see you've had a lot of things going on lately, huh...... Don't you want me to reiterate what I said to you that time, right? No matter how many things there are, we must prioritize them. ”

Gao Pragmatic was afraid to hear this, so he hurriedly said: "Yes, yes, third uncle, my nephew understands, understands." ”

Gao Gong glared at him, but thinking that his recent studies had indeed not fallen behind, and it was difficult to say anything strong and reasonable as her, so she had to let Gao Pragmatic master this degree, shook her head at the moment, and left by herself.

Several people at the table naturally got up to send each other, and Gao Gong waved his hand casually: "No need to send it, you can talk." "Just walk away, but it's also chic.

After sitting down, Gao Shishi saw that Gao Guoyan seemed to be a little curious about his third uncle's performance, so he couldn't help but touch his nose and explained in an awkward manner: "This, the third uncle acts...... Historically, uh, historically chic. ”

Gao Guoyan was a little restrained in the face of Gao Gong, but of course he would not be able to face Gao Pragmatic's little brother, and said with a smile: "I heard that Pragmatic wrote a book of "Longwen Whip Shadow", which was highly praised, and now he is the prince's companion on this basis, and his name is hung in the Hanlin Academy, which is really gratifying." ”

Gao pragmatic naturally responded with a few modest words, and Gao Guoyan said: "You are good at reading, this is a good thing, unlike my brother and me, I have always been not interested in those scriptures and poems, but I just prefer mathematics, and there is no hope in this life." ”

Gao Shishi hesitated for a moment and asked, "Brother Sanhuai, won't you participate in the tribute in the future?" ”

"Not really." Gao Guoyan said, hesitated slightly, and added: "At most, I will only finish the test for a show, so as not to be unable to speak anywhere." ”

Gao pragmatic said: "In fact, mathematics is an extremely important knowledge in the world, from the income and expenditure of the imperial court to the degree of Li Min, which is not related to mathematics?" ”

When Gao Guoyan heard this, he was a little surprised, and asked, "Why, pragmatism also knows something about mathematics?" ”

In his opinion, since Gao Pragmatic can get the attention of the third uncle in learning, it must be that he reads the scriptures very well, this kind of person in his eyes is a mind to the way of the sages, for the number of such "carving insect skills", and even "strange skills" are disdainful, why is this little brother so unreasonable?

Gao pragmatically said: "The six arts in the world are the foundation of people; Knowing a book without knowing the algorithm is like being in a dark room. ”

Gao Guoyan was taken aback: "Do you know my teacher?" ”

Gao pragmatic pretended not to know, and said with a look of surprise: "Your teacher? Who is that, and how do I know him? ”

"Oh, yes, but what you say...... It was also a coincidence that my teacher said exactly the same thing. ”

Gao pragmatic smiled: "Then the little brother has no choice but to boast of 'the hero sees the same thing'." ”

In fact, Gao Shishi was already very surprised last time he heard that Gao Guoyan worshipped a teacher who was a businessman, and later he was even more surprised when he heard that his teacher's name was Cheng Dawei. Later, he recalled it carefully, and then remembered who this Cheng Dawei was.

This is really a rare talent in the Ming Dynasty - and it is the kind of rarity that Gao Pragmatic thinks is "rare".

Because, he was a mathematician.

Cheng Dawei's name Rusi, No. Binqu, was born in Xiuning County, Anhui Province (now Huangshan City). He was born in a small businessman, he was smart and studious since he was a child, especially loved mathematics, and often spared no expense to buy arithmetic books.

When he was about 20 years old, he took advantage of the opportunity to go out to do business, invited Wu Chu, visited famous teachers, and met "Ruitong mathematicians, who are difficult to ask questions and tirelessly". He lived in a small county town and attached great importance to land surveying, and once created a "measuring scooter" and passed on the drawings to the world.

Historically, after Cheng Dawei was 40 years old, he was tired of traveling, so he "returned to Qin Si on the water for more than 20 years". He conscientiously studied the ancient books, deduced their meanings, reviewed their laws, learned from the strengths of each family, and added his own experience, and finally wrote 17 volumes of "Algorithm Tongzong" (formerly known as "Zhizhi Algorithm Tongzong") in the 20th year of Wanli. In the following six years, the book was deleted from the complicated fuss, its essentials were revealed, and four volumes of the "Compendium of Algorithms" were written, which were successively published in Xiuning.

In the "Algorithm Classics", the first and second volumes are the basic knowledge used in the whole book; Volumes 3 to 12 are compilations of various applied problem solutions, each volume is basically titled after the chapter title of the Nine Chapters of Arithmetic; Volumes 13 to 16 are "difficult problems", in fact, the algorithms are very simple, but the conditions are expressed in poetry; Relatively obscure; Volume 17 is "Miscellaneous Laws". Abacus is used for all kinds of problems in the book, and Cheng Dawei uses a set of concise and smooth abacus addition, subtraction, multiplication and division formulas and prescription methods, which have been used in the supreme pragmatic time.

The book systematically summarizes the various abacus methods of the Chinese dynasties and becomes a relatively complete abacus book. Its writing and wide circulation marked the completion of the transformation from calculation to abacus in the history of Chinese mathematics, and Cheng Dawei himself was also known as the "master of abacus". The well-known sayings such as "two one adds five" and "three under five divided by two" all come from him.

When Gao Pragmatic thought of this stubble at that time, he felt that he could simply pick up treasures on the side of the road, since his second brother was his disciple, first of all, his level would definitely not be bad, and more importantly, his "great cause" in the future would be quite in need of a mathematical master like Cheng Dawei!