Guozijian, in the Arithmetic Museum.

Everyone focused on Ke Shiqing, waiting for him to come up with the question.

"The student would like to ask the gentleman to calculate a problem in a quarter of an hour, which is 1,352 times 2,781, what is the result?"

Ke Shiqing thought about it and gave a multiplication problem with a huge number.

"Hey~, such a big number, it's estimated that it will take a day to use the calculation, right?"

"Who says it's not, this Ke Shiqing is too ruthless."

............

As early as the pre-Qin period, people learned to use the arithmetic chip to count and multiply calculations, first put the multiplier on the top, and then the multiplier on the bottom, and make the last digit of the upper number align with the first digit of the lower number, in order from left to right, use the first digit of the upper number to multiply the lower number, put the product of the multiplication in the middle of the upper and lower numbers, and then remove the first digit of the upper number, move the lower number to the right, and then multiply the second digit of the upper number by the lower number, add the product in the middle, and remove the second digit of the upper number. Until the upper number is used up, the middle number is the result.

Ke Shiqing's question, if you use the calculation chip to calculate, maybe you really have to fiddle with it for a day.

Kong Yingda and Xu Hongzhi both looked solemn after listening to the question, and their brows were tightly locked.

Li Zexuan smiled lightly, and said unconcernedly: "Hehe, what's so difficult about this, Ke Shiqing, you don't need me to do this problem at all, my eldest disciple can do it for you, Tie Dan, you come up and solve this problem on the blackboard!" ”

This is the multiplication of two four-digit numbers, with Li Zexuan's strong mental power now, he doesn't need to do it at all, he can deduce the answer directly in his mind, it is really unchallenging, it is better to let Tie Dan practice his hands.

"Yes, Master!"

Tie Dan walked from his seat to the blackboard, picked up a piece of chalk, and began to calculate using the elementary school math knowledge given to him by Li Zexuan.

He and Lan'er discovered the novelty of chalk on the blackboard last night, but they had been scribbling on it for a long time, so it was not difficult for him to write on the blackboard now.

"Hiss~ I heard you right, right? Mr. even said that this question is simple? ”

"Can that apprentice really do it?"

"It's arrogant!"

Ke Shiqing also frowned, and secretly said that this new gentleman is really a big mouthful. At that moment, he stopped talking, and concentrated on looking at the iron egg above to solve the problem, but this time, he was confused.

What is this black plank? Why can I write on it? Why is the handwriting still so legible? You can see it from so far away.

Also, what kind of words is written by the one called Tiedan? How do you look like a ghost drawing?

The rest of the crowd also noticed that something was wrong, and they all exchanged their heads and whispered about it.

"This black board is so magical, it can be used for writing, so that in the future, when Mr. gives lectures, we can listen and read at the same time, and it is more convenient to take notes!"

"Yes, my husband used to talk so fast that I couldn't remember it, but with this thing, I must be able to learn better. Now I hope that Mr. can beat Ke Shiqing, so that Mr. doesn't have to leave. ”

"Hey, what do you look at that kid wrote? How do I not recognize? ”

"Well, I don't know either, why does it look like a ghost drawing!"

..........

Kong Yingda saw Tie Dan writing and drawing on the blackboard, and instantly understood what Li Zexuan said outside the teaching hall before that he could make students get twice the result with half the effort, he had taught books for I don't know how many years in his life, so he could see at a glance that this blackboard teaching was many times better than when he was talking to books on top before.

Kong Yingda was extremely excited in his heart, and secretly said that such a good thing, Guozijian must have a set for all the teaching houses, and he had to ask Li Zexuan for a batch when he went back.

When he looked at the words written by Tie Dan, he couldn't help frowning, and thought: Could it be that Li Zexuan, who is a master, hasn't taught this child to write before? How is it written crookedly, I can't recognize it at all!

Xu Hongzhi had seen this kind of word last time, but at this moment he was still shocked in his heart, he didn't expect Li Zexuan to have the confidence to calculate such a huge multiplication problem with his strange words.

Time passed minute by minute, probably less than half an hour later, almost equivalent to four or five minutes in modern times, Tie Dan left seven lines of Arabic numerals on the blackboard, and the result had been calculated, he was still a little uneasy, and checked it again, and found that the result was the same twice, and then turned to Li Zexuan and said:

"Master, Tie Dan has been calculated, and the answer is three million seven hundred and fifty-nine thousand nine hundred and twelve."

After listening to this, Li Zexuan nodded slightly, he had calculated in his heart that this was indeed the answer.

"Grunt..."

There was a sound of swallowing saliva below, even though they didn't know if this result was right or not, but they were frightened by such a huge number, and they really couldn't understand how Tie Dan could calculate such a large number in such a short time.

"Well, Tiedan, you can sit back first! Ke Shiqing, how, is this answer correct? ”

Li Zexuan smiled, looked at Ke Shiqing and asked.

Ke Shiqing was shocked and couldn't believe it since he heard Tie Dan say the answer. When he heard Li Zexuan ask him, he came to his senses, bowed deeply to Li Zexuan, and said:

"Mr. Hui's words, the answer to this question is indeed this, but the student really doesn't understand why the question that I calculated in a day before can be calculated in half an hour. Please pass on this efficient algorithm to me, and students are willing to pay any price! ”

As soon as Ke Shiqing finished speaking, the hall exploded.

"Hiss~ That's right!"

"It's incredible, multiplying such a huge number, it can be calculated in less than half an hour, is our new gentleman the reincarnation of an immortal? How can the apprentice of the sect be so powerful! ”

"It must be the reincarnation of the gods, great, I can listen to the lecture in the teacher's hall in the future, and I can also learn this magical algorithm!"

"If I can learn this algorithm, I will definitely be able to enter the four schools next year!"

"Even the senior brother of the Four Sects Academy is not so powerful!"

………

Kong Yingda and Xu Hongzhi's eyes widened, and they almost tore off their beards.

Li Zexuan pressed his hands towards the void below, and everyone immediately fell silent, and they all turned their eyes to him.

"Shiqing, do you see these seven lines on the blackboard? This strange little character is a simpler counting method that I invented, and the calculation process is also very simple, and I will explain it to you in the future. So now, do any of you have any other questions to ask? Hurry up and ask questions! ”

Li Zexuan took a tree branch, which he had casually folded in the Guozi Prison before he came, and he pointed to the calculation traces left by the iron egg on the blackboard with the branch, and gave Ke Shiqing a general explanation.

Arabic numerals, originally invented by the ancient Indians, were later in 700 AD, when the Arabs conquered the Punjab region and captured a mathematician from northern India, the Arabs learned the counting methods and mathematical symbols of the Indians, and then spread them to Europe, and then modernized them by the Europeans.

At this time in the Zhenguan years, there were no Arabic numerals in the whole world, and Li Zexuan only thought of such a thing later, so it was not wrong for him to say that this thing was invented by himself at this moment.

Ke Shiqing couldn't help but be extremely excited when he heard that he would have the opportunity to learn this advanced algorithm from Li Zexuan in the future, he respectfully saluted Li Zexuan, and said: "Thank you Mr. for teaching, the students don't have any doubts, Mr. has found another way, his own family, and his attainments in the field of arithmetic are beyond the reach of students!" ”

Kong Yingda and Xu Hongzhi glanced at each other, and they could both see a trace of horror in each other's eyes, creating their own school, it is easy to say, but it is not easy to construct a complete and rigorous doctrine system.

Throughout the ages, people who can create their own faction and become their own family are all great masters who have been famous for thousands of years, or even great sages! For example, Confucius, Lao Tzu and others. Li Zexuan's self-created doctrine, if it can stand up to scrutiny, I am afraid that he will become a saint in the future!

Is this the prosperity of the world, the emergence of saints?

Li Zexuan was a little secretly complimented by Ke Shiqing, he waved his hand and smiled: "Okay, everyone has a question as soon as possible, there is no problem, then I will start the official class!" ”

The rest of the students all looked at each other, Li Zexuan's apprentices were so powerful, how could they dare to go out to find abuse again! So, Li Zexuan waited for a long time and didn't see anyone get up to ask questions, and he was about to start the formal class when he heard a loud voice outside the house.

"Haha, this king has a question, and I ask Dr. Li to solve it!"

……………

Thank you Tianqian Zhiyu, Xiaoyao Xiongge, Niu Niu for the reward, thank you for the monthly ticket of contentment, and thank you for the recommendation of all book friends.

(End of chapter)