North and South groceries

Luo Yong was very happy with Qiao Junlin's arrival, and he even invited the group to a meal to express his welcome.

This has never happened in the past, but these people who study arithmetic here have invited Luo Yong to eat many times. Since Luo Yong started teaching, he seldom paid for the food when he ordered food in Xu's guest house. up.

In addition, many students gave him things. Those things are expensive or cheap, but they are generally very practical. The most common one is pork and mutton. Sometimes the Luo family can't finish it by themselves, so they distribute it to his disciples , and sometimes take it to the cement workshop to give the workers extra meals.

Dr. Chen and his entourage also brought gifts to Luo Yong this time, mainly some of the four treasures of the study. Luo Yong didn't seem to use it very much, and Siniang Wulang was still in the enlightenment stage. It was a bit extravagant to give them such good things, so They all put away.

Qiao Junlin brought two manuscripts for Luo Yong, both of which he copied down word by word. The handwriting was clear and correct, and he did not know how long it took to complete.

At this time, there is no movable type printing, and all books are copied by hand, either by yourself or by paying for others to copy. Books at this time are very rare in terms of time and energy and price.

It's been half a year, and Qiao Junlin at this time looks much more stable than when they met in Chang'an City last summer.

Every time we meet, Luo Yong can see the growth of this young man. He has grown so fast that time seems to speed up on him. The current Qiao Junlin is no longer the one who came to Luo Yong to learn how to make tofu. A soft and stubborn boy.

All growth is bound to be accompanied by pain.

The perseverance and forbearance in the eyes of young people always makes people feel distressed.Sometimes Luo Yong can't help but wonder whether this person will grow up rapidly in such an acceleration, and then age quickly...

"...A few days ago we learned the calculation method of using symbols instead of unknowns, and now many newcomers have come, I'm afraid they can't keep up with our learning progress. If we start the class from the beginning, we will delay the gentlemen who came earlier. A lot of time, so I thought about it and decided to share with you the application of arithmetic in geometric structures."

When Luo Yong said these words, Qiao Junlin sat upright behind a kang table not far from him, with a pair of black and white eyes open, listening very seriously.

Perhaps it was because in the past two years, he locked himself in the room and studied hard, but now Qiao Junlin looks a lot fairer, his handsome features are soft, and his eyes are serious and persistent, yet revealing. Looking a little naive, when he looked at Luo Yong calmly, his focused expression seemed to be looking at the whole world.

In the following days, what Luo Yong showed him was indeed a brand new world.

Regarding the teaching of geometry knowledge, Luo Yong started from the simplest plane geometry. At first, he just calculated the perimeter and area, and the pace was slowed down, mainly to allow the newcomers to have enough time. Adapt to Arabic numerals and calculation methods.

The few students brought by Dr. Chen this time have generally good aptitudes, and their backgrounds are naturally good, and they are not ignorant people. They have a foundation in arithmetic before. , I don't really believe it, after all, I'm just a country boy, how can I get in touch with those really profound arithmetic methods, as a result, after taking a few classes, their thinking has completely changed.

After teaching the algorithm of the perimeter, Luo Yong began to teach them the algorithm of the area, first teaching the square and rectangle, which is not difficult for many scholars, and they often involve this aspect in their daily life , the more typical one is the calculation of acres of fields.

After the square, Luo Yong began to teach the calculation method of the area of ​​the triangle. First, he taught the right triangle. Yes, troubles started.

In fact, in the 21st century, the calculation of the area of ​​a triangle is only the content of the upper grades of primary school mathematics. At this time, they will come into contact with an important theorem, that is, the Pythagorean theorem.

Primary school students are just learning, and they don’t know how important this theorem is in life, and they don’t know that more than 1000 years ago, this theorem was still a profound knowledge that only a small number of people had access to.

When Luo used it in the living room of Xu's guest house, he used a small piece of plaster to draw a triangular shape on a small blackboard smeared with tung oil, and then drew his height with a dotted line. When readers tell about the Pythagorean Theorem, many people's hearts are shocked.

Some people are amazed at the subtlety and simplicity of this calculation method, while others are amazed that this young man who was born in a small mountain village and is nicknamed the coffin board seems to have read the book "Zhou Bi".

However, this is just the beginning. After learning the triangle, it becomes the trapezoid. After the trapezoid, it becomes the circle. In the calculations of the circle, it is necessary to design the pi.

The ratio of pi also existed at this time, and it was mentioned in Chapter Nine Arithmetic. It is usually called the "ancestral ratio", and it is calculated by cutting the circle.

However, when Luo used a simple number and a simple formula to calculate the circumference and area of ​​a circle, he didn't seem to think that this was a big deal. When teaching it to everyone, many talents really discovered that the arithmetic problems that were originally very complicated and difficult to understand in their impressions can be presented in such a simple way.

Just like what Luo Sanlang said to everyone before, what he taught was only some simple arithmetic methods, even if you are not very smart, you can apply what you have learned.

In the eyes of many people, this is the most remarkable wisdom. It explains the originally complicated things in a surprisingly simple way. This kind of wisdom of simplifying complexity is very rare in this world.

Dr. Chen originally came to Xipo Village with an attitude of broadening his horizons. He never thought that after just a few days, he would devote himself to learning.

When he is free, Dr. Chen often advises several of his students to study harder. Opportunities like today may be hard to come by in the future. For a person who is really thirsty for knowledge, he can It is definitely the luckiest thing in his life to wander in a sea of ​​knowledge that has never been reached.

Except for this old gentleman who forgot to sleep and eat, among his few students, Qiao Junlin was the one who studied hardest.

Qiao Junlin doesn't have much talent in poetry and divination. Although the cultural courses are not bad, because of his deep learning, he has a solid grasp of all homework, but what really makes him stand out is his martial arts. Wait for this time After going back, there will be another calculation.

Among the people who originally studied in Xu's Guest House, Si Niang is young, but she learns faster than many adults. Apart from talent, there is also the reason why she is Luo Yong's younger sister, so it is very convenient to ask for advice. .

After Qiao Junlin and the others came, first he was an old gentleman who was eager to learn, and soon, Qiao Junlin, who didn't even know 1234, ran in front of her, and Si Niang finally felt a little nervous. I don't think I'm smart enough to learn quickly.

Luo Yong saw that his old sister seemed to have become a little more stable after receiving some blows, and he was naturally happy to see the results. Although he is famous for being a spoiled child, he definitely has no intention of turning them into flowers in the greenhouse. , The wind and rain that should be experienced should always be let them experience it by themselves.

Thinking back to when he just woke up, Luo Yong didn't even know how to support such a large group of children at home. At the beginning, he just wanted to live a low-key life, but before he knew it, he still pushed himself into the On the cusp.

Recalling that when he was a student in the 21st century, he once learned an idiom that he understood but didn't understand: "Sacrificing one's life for righteousness".

In the long history, in the countless times of peace or war, there are always some people who, for the sake of their family, the name of the family, and the common people, put their life and death on the line, and even accompanied their own family and children. However, this was difficult for Luo Yong to understand at the time.

How could the ignorant and ordinary boy at that time think that one day he would walk the same path as those people.

Perhaps the things he did today can enable those heroes who should have died in misery to have a relatively comfortable and peaceful life.

The progress of the times has never been taken for granted. The development of human civilization is actually a process of dedication and sacrifice by countless ancestors.

But Luo Yong was fortunate to know the crystallization of wisdom in the next 1000 years in advance in the seventh century AD.Although he repeatedly reminded himself to be low-key and cautious, when he looked back, he realized that he had already walked so far. In fact, he had never slowed down his pace of progress, and he was heading in the direction where life and death were uncertain, as if it was fate.

When spring came, Luo Yong and his disciples sowed many Eucommia seeds on the hillside.

After another two years, when these eucommia saplings are roughly grown, they can start making eucommia rubber wheels.

Because Eucommia gum is hard rubber and not soft rubber, it is very suitable as an outer tire, but there is no way to do it with the inner tube. In the current situation, they can only make solid wheels. The entire wheel is made of Eucommia gum, or filled inside. Other material.

However, Luo Yong didn't know that when he was thinking about upgrading Yan Erfei's wheels, in an ordinary house in Lishi County, there was a couple who were processing Yan Erfei's inner tubes facing the kang table. At the bottom, unlike others, the two of them did not rely entirely on their hands, but made two tools that looked crude but were actually quite handy and labor-saving.

This tool is mainly composed of a wooden structure, a thousand-ply bottom inner tube, and an iron needle. Several gears are used in it. As long as they turn a handle on the wooden frame, driven by the gear and the track, the The iron needle will pierce down by itself, driving the thread through several layers of thick linen, and once the iron needle is raised and lowered, it will soon be able to pierce rows of neat needle holes on the linen.

Then the husband and wife put fine linen thread on the needle holes on the linen cloth to make a thousand-ply bottom. This method can save them a lot of effort, and the final needle thread pattern is very uniform, so they The mille-layer bottoms made by homeowners can basically be sold at a relatively good price.

If Luo Yong could see this thing, he would definitely recognize it. This is the prototype of the sewing machine.

The husband and wife did not originally make Yanerfei inner tubes, but the husband originally made bamboo chains, because he had some contact with Heng's car manufacturing company, and had seen the large and small gears used on Yanerfei, so In this winter, because he felt sorry for his young wife, he always rubbed his hands red and swollen when Nayan Er was flying the inner tube. After several attempts, he finally made such a tool, and then they found that with this tool, They could make money relatively easily by making Yanerfei inner tubes, so they started this job together.

These two people are very happy that they have a useful tool. They rush to work and earn money every day, but they don't know how much convenience this seemingly inconspicuous tool will bring to this society in the future. Little did he know that he had unknowingly become the earliest sewing worker in the world.