Happy New Year. Ten chapters were issued in a row today. I wish readers and friends a happy Chinese New Year and all the best!

When Fan Yongdou met Li Yaozong in Beijing, he was ragged, half-injured and half-sick, and he was already dying. Fan Yongdou's eyes were sharp, and he vaguely saw Li Yaozong's clear eyebrows, so he moved his heart of compassion, asked the housekeeper to give him some food, and asked a few words by the way. Li Yaozong ate something and regained a little spirit. He is neither humble nor arrogant, articulate and courteous. Fan Yongdou took up his love for talents and brought Li Yaozong back to his house in the capital to raise him. After a long time and a lot of contact, Li Yaozong's talent was gradually revealed, and Fan Yongdou was also surprised by him, and promised a high position. When the soldier died as a confidant, Li Yaozong was grateful to Fan Yongdou for his knowledge and life-saving grace, so he simply changed his name and surname, joined the Fan Mansion as a slave, and contributed to the Fan family with all his heart. Over the years, he gradually sat in the position of the general ledger with his ability and ability.

Fan Youcai studied the account book sent by Fan Yubin intently, and looked at it, his eyes gradually revealed a strange brilliance.

Fan Youcai's account book uses the addition and subtraction accounting method, and it is double-form, and all of them use Arabic numerals. The ledger only recorded the accounts of one of the Fan family's stores for three days, which was obviously just a model.

Fan Youcai stood up in a panic, called for a few large tents, and handed them the account books to read. They are all veteran bookkeepers, and they know the trick at a glance. It's a new way of keeping accounts, and it's much simpler, clearer, and more definite than the one they use now, and it's a world of difference. When everyone looked at each other, they were all sweating profusely.

When Fan Youcai told them that this account book was written by Young Master Fan Yubin, they were shocked and ashamed at the same time. Fan Youcai stood up, sorted out his long robe, solemnly arched his hand in the direction where Fan Yubin lived, and said loudly respectfully: "Young Master Yubin is really a celestial!" ”

Just after the unitary hour, the university hall of the Fan family's private school was brightly lit. The private school was full of gentlemen, students, and a dozen young bookkeepers. In the corner next to him, Fan Youcai, Fan Yuming, and Fan Qinglian also sat there quietly.

A few days ago, Fan Yubin had someone make a blackboard and some chalk. A chalkboard is a large rectangular woodblock with a thick layer of black lacquer. Chalk is mixed with gypsum, lead powder, and water and injected into an iron mold, and dried or dried. Now, the blackboard hangs on the wall and the chalk sits on the podium. There was also a stack of books neatly stacked on the podium. The blackboard and chalk attracted a lot of curious eyes in the classroom. Everyone chattered and whispered.

Fan Yubin walked in the door, and the classroom immediately fell silent. Fan Yubin nodded politely to everyone in the room and slowly walked to the podium. Fan Yubin looked around with his eyes, and caught a glimpse of Fan Youcai sitting in the corner, and there were more than a dozen young account rooms in the classroom, and he couldn't help but secretly praise this person for knowing goods and interests. When he saw the figures of Fan Yuming and Fan Qinglian, he also smiled and nodded at them.

Seeing Fan Yubin standing still in front of the podium, everyone in the classroom shouted in unison: "Hello young master!" Fan Yubin nodded at everyone with a smile, and said slowly, word by word: "I hope that next time everyone sees me, they will no longer call me young master, but sir." If you see my young age, you can also call me Mr. Xiao. If you feel that I am not qualified enough now, then you can also weigh and teach my level, and then call after thinking clearly. ”

There was a burst of good-natured laughter in the room, and the atmosphere became lighter.

Before I give a lecture, I would like to ask you a question: "If you put a bowl of boiling water and a bowl of cold water in the ice cellar at the same time, which bowl of water will freeze first?" ”

"Cold water, of course!" Let's answer it all the way. "Alright, let's do an experiment first." Fan Yubin's words were still unhurried, he clapped his hands, and two servants came in carrying a large box wrapped in cotton wool, and also brought in two pots, two bowls of different colors, one black and one white.

The servant poured water into both bowls, the white bowl steaming hot, apparently boiling, and the black bowl apparently cold. "Now let's put two bowls of water in the box and see the results later." Fan Yubin said with a smile. The servant opened the chest, and it was filled with large blocks of ice, with only a concave one in the middle.

The servant put two bowls of water into the box in front of everyone, closed the lid of the box, added a quilt to it, and then withdrew: "Everyone must remember clearly: the white bowl is boiling water, and the black bowl is cold water." ”

After speaking, Fan Yubin picked up a piece of chalk and wrote the old question of two chickens and rabbits in the same cage on the blackboard. Difficulty and difficulty. These are two old questions, and I believe most of you here will. But what I'm going to do now is a different solution. Fan Yubin's voice was not slow. He solved the easy one with a one-dimensional equation. I used the binary equation to solve the difficult one. And explain it in detail.

There were not a few low exclamations below. This solution is much simpler than going for the old-fashioned solution. After Fan Yubin finished speaking, he held up a book and said loudly: "This is mathematics, and there are many similar problems in it." Fan Yubin put down the book and continued: "It's almost time, let's see if the answer just now is correct?" ”

Then another servant entered, and opened the chest, and brought out two bowls of water, and set them before them all. "Ahh Everyone couldn't help but exclaim: It's so strange, the white bowl is obviously boiling water, but now there is a layer of ice. The black bowl is obviously cold water, and it is still the same as before, except that there seems to be a big bubble at the bottom of the bowl.

In the amazement of everyone, Fan Yubin clapped his hands again, and another servant came in with a basin, and there was half a basin of water in the basin. He put the basin where everyone could see it, then took out an egg and put it in, and the egg slowly sank to the bottom of the basin. Then, he brought in another bucket of water and slowly poured it from the side. Something strange happened: the egg slowly floated. The water doesn't pour, and the eggs are still floating on the water. Everyone's eyes widened in disbelief at this incredible thing.

Words are better than examples! Let the facts do the talking. This is what Fan Yubin has always advocated. He held up a book and said, "This is physics." If you want to know why these strange phenomena are happening, take a good look at this book. ”

There was a commotion below. When his voice calmed down, Fan Yubin continued: "If you are interested, you can choose to learn one, but only one is allowed, and you can't chew it if you are greedy." ”