Before coming to the Tang Dynasty, Li Yuanjia didn't know what "Sun Tzu's Sutra" was.

In the mathematics books in Chinese history, he vaguely knew one "Nine Chapters of Arithmetic", and he had never heard of the others, or he had forgotten them all after seeing them so many times in his previous life.

However, Li Yuanjia really remembers the question of chickens and rabbits in the same cage, because this kind of problem is too famous.

So when he saw "Sun Tzu's Arithmetic" and found that the source of the problem of chickens and rabbits in the same cage was originally in this book, he immediately understood one thing: "Sun Tzu's Sutra" must be very famous in the history of Chinese mathematics!

This book must be awesome!

The so-called chickens and rabbits in the same cage is actually a cage with chickens and rabbits, how many heads are on it, how many feet are below, and then ask how many chickens and how many rabbits.

The common question types of the Primary School Olympiad, together with the problem of releasing and filling a pool with water, will give many children a headache in the future.

Therefore, in the sixth volume of "Mathematics", Li Yuanjia put the problem of chickens and rabbits in the same cage, and then solved this problem with a one-dimensional one-dimensional equation and a binary one-dimensional equation......

How difficult can the Olympiad math problems in primary school be?

Perhaps for elementary school students, this question may still be a little difficult, but for any student who has graduated from junior high school, it is simply a question to give off.

It's just that for people in this era, what kind of thing is equation?

Simple, straightforward!

So when he saw that the problem of chickens and rabbits in the same cage could be solved in this way, Li Tai's shock in his heart could be imagined. It was only now that he came to Uncle Wang, which was already the result of his desire to finish the sixth volume to suppress the impulse in his heart.

Seeing the look of amazement on his nephew's face, Li Yuanjia was not surprised at all.

After smiling, he nodded and said, "Yes, it is precisely because I found it easy to solve these problems with Tianzhu numbers, so I wrote these six books after pondering for several years." First, I hope to write down everything I have been thinking about in the past few years, which can be regarded as an explanation of the time and thoughts I have spent; Second, I hope that more people can see the convenience of using Tianzhu numbers...... Haha, I didn't expect you to become the second person to finish reading this set of books. ”

"The second? So who is the first one? ”

Hearing this, Li Tai was a little curious, and at the same time asked a little unconvinced.

"Hehe, it's your aunt."

Blinking, Li Yuanjia smiled: "But she is still too far behind you compared to Xiaotai, even if I explain it to her every day, she has only read six books so far, and it is too early to say that she has completely learned!" ”

"Hehe, I see."

After listening to his words, Li Tai secretly breathed a sigh of relief. If he is really overtaken by a woman, his self-esteem will not be able to stand it.

Picked up the cup and took a sip of water, and after suppressing the shock, he continued to speak: "By the way, Uncle Eleven, you just said that you want more people to see the convenience of Tianzhu's numbers...... Is that why you engraved it? ”

"yes, that's it."

Nodding without hesitation, Li Yuanjia said with a sad face: "It's a pity that I have been putting this set of books in Xinhua Bookstore for a few months, and only seven sets have been sold!" And after those seven sets of books were sold, they were like a stone in the sea......"

"Sinking into the sea? Good words! ”

"Uh......"

Looking at his nephew's surprise after hearing the word stone sinking into the sea, the corners of Li Yuanjia's eyes twitched, and he felt extremely helpless in his heart - this casual idiom makes others feel like discovering a big treasure, when is the end!

simply ignored Li Tai's curiosity about this idiom, and hurriedly said: "So I'm really happy that you can come today, Xiaotai, because someone finally discovered the value of this set of books!" Xiao Tai, now the top and bottom of the Han Wangfu, whether it is an ordinary steward or a steward in those workshops outside, they have all learned to use Tianzhu numbers to keep accounts! First, it is easy to calculate, which can save a lot of time, and second, it is clear at a glance when checking the accounts; It's much harder for them to get some oil and water out of it than it used to...... In short, there are many benefits to using this Tianzhu number, and you will know if you try it later. ”

There was a smile on his face, but the taste of encouragement in Li Yuanjia's words was extremely strong.

Originally, he was expecting Fang Fengzhu to persuade Fang Xianggong to be the first to use Tianzhu digital accounting in the Liang Guogong Mansion, which opened the prelude to the popularization of Arabic numerals. However, after waiting for these few months, Li Yuanjia found that what he thought was still too simple.

People of Fang Xuanling's age are too slow to accept new things.

Li Yuanjia even doubted whether the old man could accept Arabic numerals, and if he didn't nod, counting on the two brothers Fang Zhizhi and Fang Yiai, I am afraid that Li Yuanjia would never want to see Fang Fu use it in his life.

So after discovering that Li Tai was so interested in mathematics and Arabic numerals, Li Yuanjia suddenly had a thought: If Fang Fu can't do it, is it possible for Wei Wangfu?

Teenagers are the most receptive to new things, if ......

This thought flashed through his mind, and Li Yuanjia's heart was hot, and he continued without waiting for others to speak: "Xiaotai, I won't tell you, I've been thinking about abacus recently...... It's the kind of thing contained in the "Records of Mathematics", and I want to make something that can be more easily calculated. At that time, it will be more convenient and faster to use this Tianzhu number. ”

"Abacus? "The Legacy of Mathematics"? ”

After listening to his words, Li Tai was stunned for a moment, and then his eyes showed a look of admiration: "Uncle Eleven is really studious, and he has even read this kind of book deeply!" ”

"Records of Mathematics" is a book written by Xu Yue, a mathematician in the Eastern Han Dynasty, and the existing versions in the Tang Dynasty are all annotated versions of the Northern Zhou Dynasty mathematician Zhen Luan. Li Tai is also a good book, and he has heard the name of the book before, but he has never studied it.

It is precisely because he understands the "obscurity" of this book that Li Tai admires his eleventh uncle.

A lot of books is nothing, but reading a lot of books is really awesome!

“…… Hehe. ”

laughed dryly, but Li Yuanjia didn't answer his words.

If you don't read a few books, how can you explain the mathematics he knows? If he didn't read "The Legacy of Mathematics", how could he "invent" the abacus?

"Abacus control belt four times, longitude and latitude three talents."

Xu Yue wrote this sentence, and Zhen Luan gave an explanation, which is roughly the method of abacus - a wooden board is carved into three parts, the upper and lower parts are used to stop the beads, and the middle part is used for positioning......

It's very troublesome to explain, in short, Li Yuanjia had the "inspiration" to make an abacus after seeing it.

With the foundation laid by the predecessors, what Li Yuanjia has to do is just improve and perfect, which is much more down-to-earth than complete innovation, at least there is no need to be suspected of what kind of demon it is, isn't it?

Just when Li Yuanjia thought for a moment and opened his mouth to say something, Han Lucheng suddenly walked to the door from outside, saluted the two of them and said respectfully: "King, people and things are ready......