Even though Li Chunfeng had a smile, there was still a rebellious smile on his lips. Today's Huancai Pavilion incident will probably become a story that has been circulating in Chang'an City for a while.

As our protagonist, Li Chunfeng is still immersed in the sweet village of blackness...

"Li Lang, wake up, wake up."

"Sun Weng, Chunfeng is really okay?"

"Don't worry, Master Yuan, Li Lang is fine."

Li Chunfeng felt someone slapping his cheek, and a call came from his ear.

"Li Lang, wake up, wake up..."

As his perception gradually recovered, Li Chunfeng slowly opened his eyes: "Master? Master Sun?"

Slowly sitting up from the bed, Li Chunfeng touched his head, looked around, and said, "Where is this?"

"We have already gone home." Yuan Tiangang said, "Chunfeng, how do you feel now?"

Li Chunfeng nodded and said, "Fortunately, his head was a little heavy."

Look at the sky outside, but at four or five o'clock in the afternoon, the sun sets in the west, and the sun shines on the ground through the windows, making this empty room more angry.

"By the way, what happened to Huo Xiaoyu?"

Yuan Tiangang said: "The contract has been returned to Yu Niang, and she has regained her freedom."

"That's good."

After a brief silence, Sun Simiao, who was standing beside him, said: "When I was in Huancai Pavilion, Li Lang, you can calculate such a huge number, but I don't know how it is calculated? And what is the order and what does it mean?"

At this moment, Sun Simiao's expression was serious like a student. Li Chunfeng scratched his head: "Well, it's a more special calculation method."

Speaking of this, Li Chunfeng got up from the bed, then pushed open the door and walked out of the room.

"I hope to hear the details." Yuan Tiangang and Sun Simiao also followed.

The autumn afternoon sun shines brightly on the entire yard. Li Chunfeng takes a wooden stick from the side and starts writing and painting on the ground.

"On the chessboard, the first grid is 1 cent, and the lattice behind is twice the number of the front one." Speaking of this, Li Chunfeng wrote "1X2" on the ground.

"The third grid is twice the second grid, which is 1X2X2."

"The fourth grid is twice the third grid, which is 1X2X2X2."

Having written this, Yuan Tiangang said, "Chunfeng, does the symbols here represent the number?"

Li Chunfeng was stunned, and then he began to realize that there were no Arabic numerals in the Tang Dynasty. He nodded and said, "Yes, this represents one, this represents two, and the x in the middle represents double the front."

"It's so wonderful, using symbols instead of words, but it seems much more concise." Sun Simiao learned from it. "If x represents double, then spin it into + to represent addition, isn't it the same thing?" As he said that, Sun Simiao drew a "+" sign on the ground.

"Well...this is the reason."

"If you take a single stroke of +, it will turn into - will it mean a reduction?" Yuan Tiangang also drew a stroke on the ground with a wooden stick.

Li Chunfeng looked at the two of them in surprise: "Genius, both of them are really geniuses."

Sun Simiao stroked his beard and said, "Hahaha, Li Lang is too rewarded, we are just learning from one example."

"If you take out one and look at the remaining one, it will double the two again and again. Could it be that the power of 2 that Li Lang mentioned?"

"That's right." The more Sun Simiao analyzed, the more surprised Li Chunfeng was, and he could not have imagined that the IQ of the ancients was so high.

Yuan Tiangang said: "But even with these symbols instead, I still don't know the real result?"

"Yes, what's the use of such a symbol?" Sun Simiao was also puzzled.

Li Chunfeng was also helpless. How should he explain to these two people?

At this moment, Yuan Tiangang, who was thinking alone, seemed to remember something: "Oh, I remember, there seems to be a solution in "Nine Chapters of Arithmetic".

"Nine Chapters of Arithmetic?" Li Chunfeng was stunned. He heard this for the first time.

"Chunfeng, wait for me."

After saying that, Yuan Tiangang hurried into the room, and after rummaging through the cabinets, he walked out with a very broken ancient book.

"Chunfeng, come and see here."

After Yuan Tiangang searching, a small page of characters and several pictures appeared in front of Li Chunfeng.

"Looking here, the book says, there is now a 15-step field, from 16 steps. Ask for the geometry of the field, and answered: One acre." Following the direction of Yuan Tiangang's finger, I saw a picture behind these lines of words, with a rectangle on it, and the annotation "Fifteen steps x sixteen steps are 240, one acre."

"So, the symbol ‘x’ has been mentioned in "Nine Chapters of Arithmetic", which is wonderful, wonderful." Sun Simiao touched his beard, "Li Lang, I didn't expect you to have such research on this book."

"Shame!" Li Chunfeng could only smile with an embarrassing smile. Since there is a record in the book, Li Chunfeng doesn't need to explain it.

Yuan Tiangang said: "However, how do you get two hundred and forty steps in these fifteen steps? Chunfeng, do you have any insights?"

"Ah? Oh, I think that's the case."

So Li Chunfeng picked up the wooden stick and made another doodle multiplication vertical style on the ground, muttering: "Five times six are thirty, three are zero, one is 1, one is 6, one is 5 is 5, and finally add them..."

When Li Chunfeng used the method that modern primary school students can do to calculate the result of 15x16, Yuan Tiangang and Sun Simiao were both shocked.

"I, Yuan Tiangang, at this age, I never thought I could see such a calculation technique. It's amazing, amazing."

"I'm also very eye-opening."

Yuan Tiangang praised: "This calculation method should be recorded and kept for future generations."

"It's not bad." Sun Simiao also agreed.

I saw Yuan Tiangang return to the house, bring paper and pen, and according to the method Li Chunfeng had calculated on the ground just now, he wrote: "Chunfeng and others said: "The scriptures are widely followed, and they multiply each other to obtain the accumulation step... Before this note, the accumulation of clouds was the field of mi, and the reason was understood. It is also called mi, which is complex but not appropriate. Now, the comments are made, and the materials are brief, and the materials are left to the future generations."

Yuan Tiangang wrote a lot of annotations, both powerful and accumulated, and Li Chunfeng didn't know what he was writing.

However, Li Chunfeng didn't know that he accidentally became the most authoritative annotator of "Nine Chapters of Arithmetic" in history.

After writing these, Yuan Tiangang wanted to ask again: "Chunfeng, let's talk to me carefully about this book "Nine Chapters of Arithmetic"?"

"Ah? This..." Where can Li Chunfeng understand ancient books like this? He was in trouble for a moment.

At this moment, a sound of footsteps suddenly came from the door, and then a sound came: "The King of Qin is particularly rewarded, where is Li Chunfeng?"

"Master, the King of Qin has sent someone." After saying this, Li Chunfeng walked quickly towards the gate.
Chapter completed!