That unlucky boy Yizi Lan Xiongfeng didn't tell him to go down to rest after being beaten with forty military sticks, but continued to practice shooting there.

At this time, a person came over in place of Lan Tianping and told him.

"Instructor Lan, the chief of education, please come over."

"Brother Zi'an, what are you looking for me?"

Seeing that Lu Ning was anxiously waiting for him, he realized that something was wrong.

Lu Ning looked at him and asked.

"I heard that your sister Lan Xiaoya is a talented girl, right?"

After not hearing an answer for a long time, Lu Ning took a closer look and found that Lan Tianping was looking at him with a look of disdain.

"I said, what do you mean?"

"Zi'an, it's not that you are a brother, although you have many advantages, you are too careful! It's only been a few days since I got married, and I'm actually thinking about my sister again, if Miaojin and Xinmin knew that you were such a scumbag, they shouldn't have married you in the first place! ”

When Lu Ning heard this, he replied directly and speechlessly.

"I said what do you want, our military school lacks some math instructors, can you teach?"

Lan Tianping suddenly drooped his head and replied.

"Zi'an, if you ask me to dance and ink, or even charge with a rifle, it's no problem for me to teach them arithmetic, I might as well wipe my neck directly!"

"I heard that our sister doesn't know how to count? Shall we ask her to go out of the mountains? ”

Lan Tianping thought for a moment before replying.

"My little sister knows how to count, but she is a little arrogant, and I'm afraid she doesn't want to show up, not to mention that she once said that whoever wants to discuss mathematics with him must answer three questions to him."

"Then you go back with me, and I'll go see what's wrong."

Lan Tianping looked at him incredulously, if it was said that it was a medical examination and an invention, he would not hesitate to take Lu Ning over.

But I've never heard that he can do math, and suddenly I found his unwavering eyes, knowing that I couldn't avoid this level today.

"Okay, I'll go out and be embarrassed with you, come with me."

When he arrived at the Lan Mansion, the people of the Lan family were very face-saving, blowing and blowing, and let him welcome him in, and even alarmed Mrs. Lan, and the other party heard Lu Ning's intention and sighed.

"Lord Wang, if I say anything else, I can call the shots, but I can't do it, Xiaoya, the girl's master."

"Why?"

Madame Lan sighed and said.

"Because Your Majesty likes her very much, he decreed that he would be named the county lord, and issued a holy decree to our Lan Mansion, no one is allowed to force the county lord to do what he doesn't like to do, she likes to study arithmetic, so let her study it."

"Don't hide it from my aunt, I just want to ask for math teaching, and please make it convenient."

Lan Tianping was also beside him to say good things to Lu Ning, and Mrs. Lan sighed.

"Since the prince is sincere, I will send someone to inform Xiaoya."

After a while, a beautiful and refined little maid came out, which was Lan Xiaoya's personal maid Xing'er.

He led Lan Tianping and Lu Ning to the embroidery building in the back garden.

On the way, she suddenly saw some wine jars piled up next to her, and Xing'er stopped and asked.

"Lord Wang, this is Miss's first question: Please tell Xing'er, how many wine jars are there here?"

Lu Ning took a closer look, and saw that these wine jars were arranged in a square.

The bottom layer has nine horizontal and vertical nine, the second layer has eight horizontally, eight vertically, and so on, each layer is one step lower than the next layer, a total of nine layers.

Xing'er took out a stick of incense stick and said.

"After this incense is burned, if you still can't give an answer, ask the prince to find another famous teacher to study thoroughly, and then come over to speak."

Lan Tianping was a little unhappy: "Xing'er, do you know who you're talking to?" ”

Xing'er looked aggrieved and said helplessly.

"Young Master, this is what Miss Xiaoya ordered, and it has nothing to do with me."

Seeing that the incense had just been ordered, Lu Ning stopped Xing'er.

"I'll tell you the answer directly, it's two hundred and eighty-nine in total."

After hearing this answer, Apricot almost jumped.

"Master Lu, have you also learned the gap accumulation technique?"

Lu Ning had never studied ancient mathematical works, and shook his head blankly: "What is that?" ”

"The square stack summing formula invented by Shen Kuo, a great scientist in the Song Dynasty, Miss Xiaoya studied it for three months before she learned it, even if she needs to calculate for a while, how can you come when you open your mouth?"

Lu Ning shook his head and replied.

"I don't know what you're talking about, I've only learned the summation formula for square series, and I just used a set of formulas to come out, and I still need to learn for three months, who is so stupid?"

Xing'er, who was angry at one word, turned pale and ran directly into the embroidery building, and walked out angrily after a while.

"It's just the first level, Miss's second question is out, how can you calculate it?"

As he spoke, he presented a tray, but saw a golden bracelet on it.

"Miss wants to ask you, how much does this gold bracelet weigh?"

At this time, the weights and measures of the Ming Dynasty have been unified, and all modern meters and kilograms are used for measurement.

There was a ruler next to him, Lu Ning used a ruler to measure the large circle radius of this bracelet, and then measured the small circle radius, and obtained the volume of this ring-shaped gold bracelet, multiplied by the specific gravity of gold, and then said the weight of this bracelet.

Apricot almost didn't jump and said.

"Isn't it that when we hit this gold bracelet, you were eavesdropping on the side, otherwise you don't need to use the scale, how can you figure it out?"

Lan Tianping suddenly jumped up: "Don't use me, I won't either!" ”

Xing'er didn't care about her words at all, she had already offended the eldest young master, and ran into the embroidery building in a panic.

After a long while, he came out again.

Lu Ning smiled lightly: "Did you take the third question?" ”

"This is not busy, Miss asked me to ask you, how did you calculate this annular cubic product?"

The knowledge required to derive the annular volume formula is quite complicated, and Lu Ning naturally didn't have the heart to explain it to her in detail.

"Tell your young lady, this algorithm is only known to me in the world, if she wants to learn, come to Wutang to find me."