Li Zheng put a few pieces of tea leaves into the tea bowl, soaked them in hot water and floated them in the water, tasted them and said, "Actually, I don't need too many tea leaves every time." ”

Xu Jingzong nodded enlightenedly, "Presumably, the old generals are used to cow chewing peonies." ”

"How's the soap ready?"

"I made a thousand bars of soap in three days."

Following Xu Jingzong to the soap workshop, when passing by the printing workshop, Li Zheng Yuguang noticed Li Jiangshan standing in the attic of the printing workshop staring at him.

Today's Xu Jingzong has become the second-in-command of Jingyang Village, and like Li Yifu, he is in charge of the production and manufacturing in the village.

These two men have good skills.

Regardless of their character, they are still very good second-in-command.

They are very handy in dealing with the idle affairs in the village.

Li Yifu was in charge of most of the workshops in the village, as well as road construction and manpower arrangements.

Xu Jingzong is more of a contact with the outside world, and he is very familiar with the officialdom.

Some of the workshops where Li Yifu has no energy, or can't manage it, have already arranged for Xu Jingzong to watch.

Li Chunfeng had already arrived in the village and began to teach the children here mathematics.

Everything is in order in the village.

Li Chunfeng explained to the children that it was a problem of chickens and rabbits in the same cage.

"Chickens and rabbits in the same cage, a total of thirty heads, eight out of eighty feet, how many chickens and rabbits in the cage,"

After the question was finished, Li Chunfeng said with a smile: "Does anyone know the answer?" ”

This is the title of Sun Tzu's arithmetic.

Li Chunfeng expects the children to scratch their ears and cheeks, and expects the children to ask for advice.

When I first calculated this problem, it took me more than a month.

I have to sigh that Sun Tzu's calculations are profound.

But the scene in front of me was a little different from what I expected.

There was silence in the classroom, and there were even children sleeping.

Looking at the casual learning attitude of these children, all of whom may not have been understood by rural children, Li Chunfeng sighed, "Your county marquis asked me to teach you mathematics, the way of mathematics is broad and profound, even if it is a poor way, it has not reached the end of what he has learned all his life." ”

Da Niu opened his mouth and said, "Daoist Li, can you come up with some difficult questions." ”

"It's hard to ...... It's a little harder. Li Chunfeng looked at the question he had written with charcoal on the wooden board in amazement.

Da Niu, who is the squad leader, said: "This question is too simple, we will do it." ”

"Simple ......"

Li Chunfeng looked at his own questions, and then at the students who were doing it.

The question of this chicken and rabbit in the same cage is difficult for many Chang'an students, and even the students of Guozijian may not be able to answer it.

Li Chunfeng said: "Okay, what is the answer to this question?" ”

The big bull opened his mouth and said, "There are sixteen chickens and fourteen rabbits." ”

"Huh?"

Li Chunfeng looked at the question behind him in surprise.

Again revised a few numbers in the title and asked again, "And now?" ”

Da Niu said helplessly: "Thirty-three rabbits, twenty-six chickens." ”

Li Chunfeng was surprised to change a few more numbers.

Big Cow: "Twenty rabbits, twelve chickens." ”

Changed back and forth several times.

The big bull answered like a stream.

Li Chunfeng looked at the child with a nervous expression, "How did you figure it out." ”

Da Niu smiled reluctantly, "Teacher County Hou has taught." ”

"Then how did you calculate so quickly?"

Li Chunfeng asked again.

Li Zheng's mathematical realm is very high, and Li Chunfeng thought in his heart that maybe Li Zheng's mathematical realm is even higher than himself.

Unexpectedly, Li Zheng actually taught the children of Jingyang.

Da Niu listened to Li Chunfeng's question, and replied respectfully: "Actually, the trick of this topic is very simple, and the teacher taught us a formula. ”

"Formula? What mantra? ”

Li Chunfeng is nervous? Could it be that Li Zheng has a better algorithm? Can even children learn? If that's the case, what is the arithmetic that I have been adhering to for most of my life?

The class was very quiet, and Da Niu read aloud: "Suppose it's all chickens, suppose it's all rabbits." How many feet are more, how many feet are missing, divided by the difference in feet, is the number of chickens and rabbits. ”

“……”

Li Chunfeng frowned and touched his chin and pondered, and said after a while: "You read the mantra again." ”

Da Niu recited the mantra again.

Stunned in place, Li Chunfeng's mind kept echoing the mantra recited by Da Niu.

It does, and it's much simpler.

Raising his eyes at the students here, Li Chunfeng asked again, "Could it be that you all know?" ”

"We all will." The students said aloud in unison.

A group of children around the age of ten can already do the questions on the scriptures of their grandson?

What kind of monsters did Li Zheng teach?

There are only a handful of people in Chang'an who can calculate this problem.

There is also this formula, knowing this formula, it is indeed a lot easier to use the formula to calculate the same cage of chickens and rabbits.

Just apply the numbers.

A question that stumped so many people in Chang'an became so simple in Li Zheng's hands?

This may be the reason why it is better to teach a man to fish than to teach him to fish.

Avoiding the eyes of these children, Li Chunfeng was a little flustered and cleaned up the scrolls in front of him.

Clearing his throat, Li Chunfeng wiped the cold sweat from his forehead and said: "Since you all know, it will be easy for the poor road, why don't you have any questions that you can't do, you can ask the poor road." ”

"Yes!" Da Niu immediately said.

Li Chunfeng took a step back, facing the half-year-old child in front of him, who looked like he was only ten years old, and he was inexplicably a little panicked.

The big cow drew a huge square on a piece of paper, which was made up of forty-nine small squares to form a seven-by-seven square.

After seeing that Da Niu finished painting, Li Chunfeng asked, "What is this topic?" ”

Da Niu said: "This is the question taught to us by the county teacher, this figure is composed of forty-nine small squares, how to cut so that the shape of this figure remains unchanged, and it is just an empty piece." ”

Li Chunfeng stared at the figure in front of him and said, "You have to be clearer." ”

Da Niu looked at Li Chunfeng and said: "Forty-nine small squares are cut, how can it become forty-eight pieces with the same shape." ”

Li Chunfeng blinked and said, "Isn't it okay to cut a piece?" ”

"No, forty-nine pieces can't be missing, and the paper material can't be redundant, but there will be one less piece after cutting and re-splicing."

"How is that possible!" Li Chunfeng looked at this figure and said, "If you don't cut off a piece, how can you make this picture lose a piece out of thin air." ”

"Indeed, the students also find it difficult, and the teacher has hinted that it is related to the Jiugong connection."

Nine Palaces Connection? Li Chunfeng had naturally heard of this question, and at that time, Li Zheng used it to test those children with five surnames.

At first, I also tried to use five straight lines to connect the nine palaces, no matter how you draw them.

And Li Zheng's painting method can be done with four straight lines, which is like reducing one painting out of thin air and connecting the nine palaces.