Volume 1: The Unsettled Teacher Chapter 10: Cao Cao Becomes a Disciple? ???

  As early as the Spring and Autumn Period, Warring States Period, great ancient Chinese people invented multiplication formulas, but truly proficient people are really rare. Cao Cao is considered a high-level intellectual, he thought for a moment;

  "I am thirty-six years old this year. My youngest son Cao Pi is seven times younger than me, and there is still one year left over. How old is my son Cao Pi this year?"

  Yeah! As expected of Cao Cao, he has a strong reverse thinking mind. He actually gave Li Yu a division problem, you know that at this time there was no such thing as division, although division can be considered as an auxiliary product of multiplication, but it wasn't named yet;

  Li Yu said without hesitation: "Cao Pi is five years old this year, right?"

  Cao Cao was taken aback and clapped his hands: "Judging from Mr. 's calculation speed, Mr. is indeed proficient in arithmetic. Now, let Mr. test me too!"

  Wow! Want to show off a bit? Li Yu rolled his eyes, looking at the meat in his hand: "I eat one catty of meat today, and I'll eat one catty tomorrow, day after day. After a month, how much will I have eaten?"

  "Sir treats me with sincerity!", Cao Cao frowned in dissatisfaction;

  Li Yu knew that he couldn't afford to offend this big boss, so he said: "In the southern country, there is an animal called an elephant! It's two zhang tall and weighs who-knows-how-much..." "Is there really such a strange creature?" Cao Ren interrupted Li Yu in surprise.

  Li Yu angrily shouted: "In the classroom, no random talking is allowed! If you have something to say, raise your hand!", Ah... Li Yu was greatly embarrassed... This was his professional habit, which scared Cao Ren into shrinking his neck. Li Yu smiled awkwardly and bowed: "Professional habit, sorry..."

  "Please continue, sir!", Cao Ren replied with a bow, and didn't mind;

  "If some elephants and horses are put together, their average weight is 8,000 catties. It is known that there are 50 elephants with an average weight of 10,000 catties each, and the average weight of a horse is 3,000 catties. How many horses are there?"

  Cao Cao was somewhat dizzy, he picked up his pen and wrote the question given by Li Yu on a bamboo slip, thinking for a long time, but he couldn't figure out how to calculate it.

  "Cough, cough! I'm not feeling well, so I'll take my leave first, Lord Cao. Take your time!" Li Yu bid farewell and left with a servant, while Cao Cao was still not as cunning as he would later become and was somewhat concerned about the competition. After all, it's in a man's nature to be competitive! As they departed, the crowd remained oblivious, engrossed in the intriguing math problem.

  Only Xu Chu wanted to escort Li Yu, but was stopped by Li Yu's waving hand. He pointed to his own chest, indicating that he should not forget what he had said and the responsibility he bore. Before Li Yu came, he told him that from now on, he would have to disown six relatives, even if it were himself, and without Cao Cao's permission, he could not let himself enter his room, and must follow Cao Cao closely, not leaving an inch.

  He slept for more than a few hours, and nearly three hours later, Li Yu was shaken awake by Le Jin; "Oh? General Le, what's the matter?" "The master is calling you to come with me," "Hmm!"

  As soon as Cao Cao entered the room, he saw Li Yu stunned for a moment, then eagerly said: "Hehe, there are twenty horses!"

  He looked at Cao Cao with a hint of doubt, then walked forward a few steps. He casually picked up an unused bamboo slip and took up a brush to write down several formulas. After looking at the answer he got, he said calmly, "Right!"

  Cao Cao was stunned, and the other generals were also stunned! Cao Cao spent more than an hour, using countless bamboo slips, calculating back and forth countless times to get the answer. This guy had casually drawn a few symbols that he couldn't even understand himself and already got the result. Cao Cao looked at Li Yu with some unwillingness, but couldn't find any mistakes.

  Li Yu naturally saw the drafts all over the floor and said with a hint of amusement, "You're not...", Cao Cao's face suddenly became hot.

  What a nearly two-thousand-year-old culture! Li Yu felt an unspeakable pride in his heart at this moment, and he glanced at the ashamed Cao Cao, secretly saying to himself, Boss, sorry about that, I just wanted to make a living.

  ……

  "Meng De has something unclear, please teach me!" Cao Cao had always loved talent, and this was undeniable whether in official history or fiction. At this time, he addressed Li Yu by his own courtesy name, obviously putting Li Yu in a very high position in his heart;

  "Please speak, Duke Cao!" Li Yu's current mood is very good, it seems that he will occupy an important position in his heart.

  "Meng De just calculated the problem given by Mr., and had a vague feeling of some unknown connection, but couldn't quite grasp it. Please, sir, enlighten me on how to solve this problem..." Cao Cao stood up, and under the disbelieving gaze of Xiahou Dun and others, paid respects to Li Yu as if he were his teacher.

  Li Yu hastily helped Cao Cao up, "Kill me too!", but in his heart he was extremely pleased! Then he explained;

  "What Cao Gong said is right, you see... " Li Yu picked up his pen and took a bamboo slip, saying as he wrote, "The weight of the elephant is two thousand catties more than the average, and the weight of the horse is five thousand catties less than the average. There are fifty elephants, which means an excess of one hundred thousand catties. Using the method of supplementing the deficiency with the surplus, we can calculate that the number of horses is... "

  "What's going on here?" Cao Cao's eyes lit up, and he snatched the pen from Li Yu, starting to write on the paper. Whoa! I haven't finished speaking yet! Li Yu stomped his feet, feeling a bit displeased. It took me so much effort to show off, but you little brat didn't want to?

  "Indeed!" Cao Cao exclaimed, his eyes gleaming with excitement. This is about right, Li Yu was very satisfied, "Using the number of jin that exceeds the average value of the elephant to divide the number of horses below the average value..."

  "Wait! Divide!" Cao Cao was shocked in his heart, "What is divide...", "Uh..." Li Yu was speechless for a moment, "This..." He suddenly woke up, at this time what... division method;

  "What's wrong?" Cao Cao muttered a sentence, his face showing a strange expression as he stared at Li Yu who had stopped abruptly.

  "...Don't look at me like that, I'm not a good man. Li Yu was looked at by Cao Cao with a chill running down his spine, and the eyes full of desire for knowledge deeply burned Li Yu's face."

  "Alas..." Cao Cao sighed, only now realizing that he had just lost his composure. This Li Yu... no, Master Huai De's technique was absolutely unknown to anyone in the world. He had actually dared to ask so carelessly, if it could be passed down, unless it was to a close relative?

  Cao Cao couldn't help but burst out laughing: "Sir, you're a genius! I, Meng De, am deeply impressed!", "I'm ashamed, I'm ashamed... Ah, boss, it's getting late...", Li Yu saw that these few people were staring at him deadpan and awkwardly rolled his eyes.

  "What is a boss?" Cao Cao couldn't help but ask curiously. "Ah, it's like this, Lord Cao, you are like the big landlord, and I am like the long worker. Isn't the landlord always scolding the long worker with a stern face? It's just like that, a boss is someone who always has a stern face!"

  "Haha!", Li Yu's words made Xiahou Dun and several others burst out laughing. "Sir..." Cao Cao's one sentence suddenly made Cao Ren and several others stop laughing in shock. "Uh... is there something?"

  Cao Cao furrowed his brow, clearly struggling inwardly, but ultimately he made a decision. He walked up to Li Yu and surprisingly paid him a grand courtesy.

  "Big brother......" Xiahou's two brothers and Cao's two brothers shouted in unison, this is the etiquette of a junior! If the previous one was just a show of respect for Cao Cao, then this bow almost solidified Li Yu's position! Teacher ah!

  Cao Cao ignored the two pairs of brothers and stared at Li Yu with a burning gaze, "Meng De is willing to pay respects to you as his elder brother, I hope you can teach me this technique..." Li Yu opened his mouth in surprise, he didn't expect that he would become Cao Cao's teacher! He was taken aback, after a moment of stunned silence;

  "It's not possible, Lord Cao!" Li Yu hastily helped Cao Cao up. Good grief! Are you trying to blind me with your words? Look at Xiahou Dun, Xiahou Yuan, Cao Ren and Cao Hong, they're all staring at me as if they want to kill me with their eyes: "As a subordinate, I should not dare hide anything from my lord. I am not one to hoard things for myself! To be honest, this is a method I came up with on my own, it's actually just the inverse of multiplication!"

  Li Yu silently prayed in his heart, "Forgive my shame, all you wise men of the past! For survival's sake!" "What is he muttering to himself?" Cao Cao couldn't help but wonder.

  "That's right! The teacher used to teach at Xujiazhuang, and many children know it!", Xu Zhu interjected in a loud and clear voice, "Then do you know it too?", "Uh... I'm not talented... didn't learn it...", Xu Zhu replied awkwardly to Cao Ren's question.

  "That's it!" Li Yu picked up a bamboo slip and took up a brush to draw out a few symbols, explaining the application of Arabic numerals with these symbols.

  "Great talent, sir! Meng De admires you. From today on, this Arabic numeral will be added to your name. The Li's calculation method will also make a name for itself in the world. I am willing to offer you the position of chief accountant, but I don't know if you would condescend to accept it!" - Cao Cao

  "I will do as you wish, I dare not disobey!" Li Yu immediately kowtowed. Having said that, if he didn't give face, he would be worried that Old Master Cao would cut him down with one knife: "I have seen the master!" "Haha! With Mr.'s help, it's truly a blessing for three lifetimes. Come on, open the banquet and welcome Mr.!

  Although the wine of the Han Dynasty was like horse urine, Li Yu still endured and drank a lot. At the banquet, Cao Cao also made rounds to toast with everyone, especially Xiahou Dun, that enthusiastic guy, don't even mention it! When Li Yu walked back dizzily.

  Cao Cao paid no attention to Xu Chu's presence, and said to Xiahou Dun, Xiahou Yuan, Cao Ren, and Cao Hong: "Look at Mr. Huai De!"

  "What a rare talent in the world! Li's calculation is indeed remarkable, and the Arabic numerals have reduced the difficulty of calculation. From now on, it will be much more convenient for military campaigns and grain statistics! When there is time, I must listen to his teachings!" Xiahou Dun had already admired Li Ye at this point, so he naturally praised him without reservation.

  "Haha! Yuanrang, don't you resent him for scolding you as a matchless rogue?" Cao Cao couldn't help but tease with a smile. "Uh, this... let's not mention it now!" Xiahou Dun rubbed his nose.

  "Big brother, this Li Yu and Huai De are men of great talent despite their humble origins. Just now, when they spoke about the matter of summoning the troops, it's clear that they have exceptional abilities! Congratulations, big brother, on having such a talented assistant! ", Cao Ren thought to himself, "This kid is still feeling pleased from Li Yu's praise and still remembers his kindness!"

  "Erudite and generous, without the pedantry of a scholar, he's quite good! With his help, big brother's affairs are promising!" - Xiahou Yuan

  "Haha, not bad, I said that getting a mighty general is better than ten million gold and silver, but there's another sentence behind! ", Cao Cao smiled smugly. Cao Hong immediately asked: "Oh? What is it?"

  "To obtain one great talent is better than having a thousand soldiers and ten thousand horses!"