Half an hour later, the crowd walked in front of a house. Pen? Interesting? Pavilion wWw. ｂiquge。 info Xin Yue looked up and saw the word "Zhang Fu" on the plaque on the door, and then he realized that Cai Yong was staying at Zhang Zhao's house.

……

Xin Yue, Cai Yong, and Zhang Zhao talked while drinking. Cai Yong asked Xin Yue: "Xin Yue's little friend came all the way from Qingzhou, I don't know what happened?" ”

Xin Yue thought, he can't say that he wants to come to find those talents of the Three Kingdoms in the future, and he wants to dig the foot of the wall in advance! So he could only reply: "I traveled this time, one is to study, Xin Yue has been practicing martial arts since he was a child, and he has less classics, so I hope that this trip can find a good teacher and learn the classics." ”

Hearing that Xin Yue wanted to find a teacher, Cai Yongke was interested, you must know that Cai Yong has countless students, and there are many disciples, Wang Cang, Gu Yong, Ruan Yu, Lu Cui, and others are all outstanding, and there is also Cao Cao, who is also a disciple of Cai Yong, which shows that Cai Yong still has a lot of say in this regard.

So Cai Yong asked: "I don't know where Xin Yue Xiaoyou wants to find a good teacher?" In fact, Cai Yong saw that Xin Yue's temperament was dusty, and his conversation and cultivation were very good, so he also had the intention of thinking about it, if he was qualified......

Xin Yue could only answer Cai Yong's question: "I haven't thought about it yet, I can only travel around and see opportunities." ”

At this time, Zhang Zhao listened to the conversation between the two on the side, and knew that Cai Yong had the idea of considering Xin Yue, so he helped and said: "Oh, Brother Xin Yue, don't you know that Mr. Cai is the world's educator, and there are countless students and disciples?" If the Xin Yue brothers are interested, they may wish to ask Mr. Cai for advice. Zhang Zhao also hopes that Xin Yue can become Cai Yong's disciple.

Xin Yue doesn't want to apprentice to a teacher, the so-called "a teacher for one day, a father for life", and he has to fulfill his responsibilities and obligations after worshipping a teacher.

But although I think so, it's not easy to thin Cai Yong's face now, and with Cai Yong's master, his name can be more legitimate and loud.

Xin Yue worshiped Cai Yong as a student, so he also called Cai Yong Mr. in general with Zhang Zhao, and also asked Cai Yong some questions.

Time passes imperceptibly......

During the discussion, Xin Yue heard Cai Yong talk about his research on astronomy and arithmetic, which made Xin Yue suddenly remember that the development of mathematical problems in arithmetic in the Eastern Han Dynasty due to production and life has become a specialized discipline, but there are few researchers. In addition, because records are written in kanji, they are very lengthy and complex, making it difficult to spread among the general public.

Who can match his own arithmetic from later generations today?

Xin Yue asked: "There is a pool, the surface of the water is a square with a side length of 10 feet, and in the middle of the pool there is a new reed, which is 1 foot above the water surface, as shown in the figure below, if you pull this reed vertically to the shore, its top just reaches the surface of the water on the shore. So how deep is the water? How long do reeds grow? ”

This problem, if Cai Yong is asked to calculate it in a short period of time, it is indeed difficult.

Xin Yue didn't ask this question to endanger Cai Yong, so he asked someone to find a pen and a piece of cloth brocade, and then wrote:

Water depth: x feet, then the length of the reed is: (x + 1) feet,

According to the Pythagorean theorem: x2+(

10

2

)2=(x+1)2，

Solution: x=12 (ruler),

The length of the reed = x + 1 = 12 + 1 = 13 (feet),

Answer: The pool is 12 feet deep and the reeds are 13 feet long.

Seeing the content on the cloth, Cai Yong and Zhang Zhao just looked at Xin Yue blankly.

So Xin Yue could only explain to the two: "× means unknown ......, 1, 2...... These represent one, two, ......"

After a detailed description, the two of them finally barely understood, and they were very surprised, this is too unbelievable, it usually takes several days and nights to complete the problem, and a few symbols and numbers under Xin Yue actually did it.

Cai Yong, who has studied arithmetic, even left behind the idea of wanting to accept Xin Yue as a disciple just now and the displeasure that Xin Yue did not have an apprenticeship, and patiently asked Xin Yue for advice.

Xin Yue saw Cai Yong's appearance, and talked about some basic mathematical knowledge of Arabic numerals, addition and multiplication rules, etc.

Cai Yong wondered where Xin Yue learned this knowledge, so he asked: "I don't know how Xin Yue Xiaoyou learned this knowledge, I pride myself on having a wide range of knowledge, but I have never heard of Arabic numerals or anything." ”

Xin Yue knew that no matter who it was, it would feel strange.

So he explained half-truthfully: "Sir, do you know that Emperor Wu sent Zhang Qian to envoy to the Western Regions?" ”

Cai Yong and Zhang Zhao were surprised that Xin Yue didn't answer but mentioned this, but they knew that since Xin Yue said this, there must be something to say.

So he replied, "Of course I know, as a big man, this is my pride." ”

Xin Yue nodded and continued: "Since this is the case, then Sir should know that the Western Regions are not deserted, but there are many countries. ”

"Of course I do."

"Although everyone knows about the existence of the Western Regions, due to the corruption of the imperial court now, it has been sending envoys to contact and explore the affairs of the Western Regions for many years, so everyone's understanding comes from historical records." Zhang Zhao also added.

Xin Yue continued: "But what I want to say is that the Arabic numerals I use are from countries in the Western Regions. ”

The two were shocked, but they didn't lose their temper, but looked at Xin Yue, hoping that Xin Yue would continue.

Xin Yue saw the expressions of the two, and knew that the two of them wondered why Xin Yue was able to learn the knowledge of the countries of the Western Regions, so he continued: "Sir doesn't know, although there are no envoys from the imperial court to communicate with the countries of the Western Regions, there are still merchants who have dealings, so the people still have contact with the Western Regions. And in the far reaches of the Western Regions, there are now several powerful empires, not even inferior to the Great Han ....."

Hearing this, Cai Yong immediately stood up and exclaimed, "What, no less than the empire of the Han Dynasty?" ”