Just when Fang Xuanling looked confused, Zhao Shuixian wrote a number in lowercase letters on the paper: nine times nine equals eighty-one.

Fang Xuanling took the paper and saw the calculation on it, and said: "The sum of nine nines becomes the number of nine crosses and nines?"

"Sir, this cross is called multiplication. Little girl, please give me a calculation formula."

"good."

Zhao Shuixian wrote another number 111 times 111 on the paper and said: "Sir, 111 times 111, if you add them up, do you need to add 111 times?"

Fang Xuanling nodded and said, "That's right."

Zhao Shuixian smiled and said: "Adding 111 times is too tedious, so the young master invented multiplication. Just multiply two 111 together and do a simple column calculation, and you can get the answer quickly.

12321, Your Excellency, this is the answer, please take a look."

Zhao Shuixian handed Fang Xuanling the answer he had just calculated.

Fang Xuanling took the paper doubtfully and thought to herself: "This is too fast. I have just added the twelfth 111."

As if seeing Fang Xuanling's doubts, Zhao Shuixian said: "Your Excellency, you can test both of us at any time."

Fang Xuanling said: "Okay, then I will ask another question and you will tell me the answer."

"My lord, please give me a question."

Fang Xuanling thought for a while and said: "What is the value of 121 times 125000, then times 3?"

After Zhao Shuixian and Qiao Yan memorized the numbers, they quickly calculated on the paper. After about three minutes, they put down their pens almost at the same time.

"You guys are coming out so soon?" Fang Xuanling said in shock.

"Please take a look, sir." Qiao Yan and Zhao Shuixian handed the paper with their answers to Fang Xuanling at the same time.

Fang Xuanling took the calculation paper doubtfully and was shocked when he saw two identical answers. It was really calculated so quickly.

4537500, this answer is correct. A group of clerks from the Ministry of Revenue calculated it after staying up all night for several days.

However, now people can calculate it in just three minutes. Does this mean that the officials in the court are too incompetent, or is Li Feng's mathematics too outrageous?

After retracting his thoughts, Fang Xuanling said: "Your answer is very correct. Is there any multiplication operation in this math book?"

"Yes, there are not only multiplication operations, but also addition, subtraction and division operations. Adults should know about addition and subtraction. As for division operations, they are just the opposite of multiplication operations.

Multiplication is the addition of several numbers, and division is dividing the result by a known number to get another number." Zhao Shuixian explained again.

Fang Xuanling half-understood and said, "As long as it's in the book, there will be people in the court studying it. I'll take the math book and the abacus away first."

"Your Majesty, please excuse me."

When Fang Xuanling was about to leave, Qiao Yan and Zhao Shuixian came out to see him off at the same time. As for Li Feng, Fang Xuanling had no intention of letting him come out to see him off.

In order to avoid Li Feng asking some questions that would embarrass Fang Xuanling.

Not long after Fang Xuanling left, Li Feng walked out of the office and waved to Qin Huaiyu.

Qin Huaiyu immediately put down his work, trotted up to Li Feng, and said, "Teacher, what are your instructions?"

Li Feng asked: "Where is the coal?"

"Teacher, what do you want coal for?" Qin Huaiyu asked.

"I'm asking you, where do you come from with so much nonsense?" Li Feng asked unhappily.

Qin Huaiyu said: "Yes, there is a coal mine in Taiyuan, and there is also one near the capital, but it is in the hands of Mr. Pei Ji.

But mentor, I think it would be better for you not to ask him?"

"What's wrong?" Li Feng asked in confusion.

Qin Huaiyu explained: "Master Pei is the confidant of the Supreme Emperor. Because of His Majesty's relationship, the Supreme Emperor was forced to abdicate and lived in the palace all year round without any freedom.

Therefore, if Lord Pei does not deal with His Majesty, he will often object to His Majesty's proposals. Even if he knows that the matter is beneficial and harmless, he will still object.

Your Majesty wants to kill him for this, but due to the Emperor's reputation, plus the fact that he has many followers, and the most important thing is that Pei Ji has made great contributions and is old, Your Majesty is embarrassed to deal with him."

Li Feng nodded and said: "I understand, not only is he arrogant due to favor, but the person who favored him is still a person from the past. It's just that your Majesty cherishes his own reputation. But believe it or not, he will be dismissed from office in less than a month.

"

"Teacher, do you want to deal with him?"

Li Feng laughed and said: "As long as you know it, don't spread it randomly."

"Teacher, do you want my dad to help?"

"No. I just came to ask him about buying a coal mine. It would be best if he is willing. If not, then he will just wait to be dismissed from office and sent to another job." Li Feng said.

"Then he probably won't agree." Qin Huaiyu said with great disdain.

Li Feng smiled and said, "How about I make a bet with you, my master?"

"What are you betting on?" Qin Huaiyu asked.

Li Feng smiled and said: "Of course it's not gambling. Let's do this. If I can't get the coal mine within a month, then I will let you and Cheng Chumo finish the course of sharpening your character early."

"Then what if the mentor wins?"

Li Feng thought for a while and said: "If I win, you will start living in the store. You will also be responsible for sweeping, mopping, cleaning the door and other tasks every day."

"Okay, I agree."

"Don't be so anxious. You go ask Chu Mo and see if he is willing. If he is not willing, I will fight with you alone. Whether he wins or loses, it has nothing to do with him."

"Okay, I'll ask him."

In the end, Cheng Chumo also agreed to bet with Li Feng.

Fang Xuanling returned to the palace with his math book and abacus. This time he wanted to show off. Recently, Li Er was the one showing off every time, so he had no chance.

"Xuanling, why are you back? Leave the imperial decree to Li Feng." Li Er asked.

Fang Xuanling immediately laughed and said: "Your Majesty, the imperial edict has been handed over to Li Feng, and he expressed his understanding. At the same time, he gave the minister two things."

Li Er looked at the book and abacus in Fang Xuanling's hand and said, "These are the two things in your hand."

"Exactly." Fang Xuanling held up the abacus and said, "This is the abacus. Your Majesty, I will demonstrate it to you."

Immediately afterwards, Fang Xuanling straightened the abacus up and down, began to fiddle with the beads with his right hand, and said: Your Majesty, this abacus has another formula, one up one, two up two nine up nine; two down five down three, three down

Five goes to two, four goes to five and goes to one.”

"Click, click"

Li Er watched Fang Xuanling fiddle with the abacus beads and listened to the formula in his mouth. Li Er's eyes lit up. This is a special accounting tool. It has an abacus and a new accounting method.

The accounts of the Account Department will be clearer.

Shopkeepers all over the world can keep accounts and settle accounts more easily.

After Fang Xuanling finished speaking a set of formulas, he also finished his abacus.

"Good stuff, produced by Li Feng, must be of high quality. Fang Xuanling, publish both the abacus and the abacus formula, so that the common people know the wonderful use of the abacus, and spread it in the name of Lantian Hou.

Li Feng suffered a loss due to the imperial edict, this time I will give him a good name." Li Er said with a happy smile.

"Yes." Fang Xuanling said.

Then he took out his mathematics book and said: "Your Majesty, this book is mathematics. It was written by Li Feng. Wei Chen was shocked by it. It is a book on the application of lowercase numbers.

The book contains operations methods for addition, subtraction, multiplication and division. Among them, Weichen will not explain the addition and subtraction.

Only this multiplication method, I think it should be made public to the world."

Li Er frowned and said, "What is multiplication?"

"Your Majesty, I also have a formula for multiplication. One by one is one, and one by two is two hundred ninety-nine and eighty-one."

"The formula is catchy, but I still don't understand the multiplication method." Li Er said.

"Your Majesty, I have two calculation questions here, please take a look." Fang Xuanling handed Li Er the calculation questions written by Qiao Yan and Li Shuixian.

Li Er looked at the calculations on the paper, frowned slightly, and said, "I seem to understand a little bit. Xuanling, please send this book and the abacus to Hongwen Hall."

"Yes." Fang Xuanling responded disappointedly.

Li Er smiled and said: "Xuanling, don't forget, what is our most important task now?"

"I dare not forget. I also mentioned this matter to Li Feng. He is preparing."

"That's good. If you need anything, just ask Li Feng and I'll definitely satisfy him."

"Weichen will tell him."

"Well, the four of you should discuss it carefully. I hope to see the red cannon before next year."

"Wei Chen believes that Li Feng will not disappoint His Majesty."

"He has indeed never disappointed me, but I worry that the greater my hope, the greater my disappointment."

"I'm here to confirm again."
Chapter completed!