Ling Han said: "That's the case, the last time I went to the Iron Buddha Temple with my mother to worship the Buddha, during the break, Master Huizhen asked me a question, the topic is like this, 'Every time the Iron Buddha Temple has a night dinner, three people share a dish, four people share a soup bowl, and five people share a bun basin, it is known that there are a total of 470 plates, bowls, and basins. ’”

Ling Han just knew that Liu Fan was not familiar with the slightly more quaint literary language at all, so he basically said the topic in the vernacular.

As soon as Liu Fan finished listening to the question, he thought to himself, this question can't be solved, so arithmetic is still difficult to meet opponents? Impossible, I looked at this girl again in disbelief, and sure enough, I found a trace of cunning in her eyes, and I was even more sure in my heart, it turned out that this was a test question that the little girl came out of first, it was really unseemly, I thought this little girl was a sincere person.

His mouth replied, "Wait a minute. ”

After a few random strokes on the ground with his finger, he immediately replied, "Six hundred monks, two hundred plates, one hundred and fifty bowls, and one hundred and twenty basins." ”

As soon as these words came out, the three people in the hall were immediately shocked.

The Li brothers and sisters and Ling Han are good friends, they have watched this girl grow up since they were children, and they have heard a lot about Ling Han's arithmetic, and they know that although this kind of problem is not very difficult, it will take at least half an hour to solve it with arithmetic, and this kid solved it almost instantly, Ling Han and Li Min looked at each other, one was stunned and the other was flustered, and they all thought that this was absolutely impossible.

Sure enough, after only a while, Li Min immediately said: "Liu Fan, have you solved this question before, no, Han'er, this person may cheat, and then try to re-debut the question." ”

Ling Han also had a suspicious look on his face, and said, "General Liu, we are all a little incredible, I'm sorry, I have to continue to ask questions." ”

Liu Fan said in his heart: "The first test question has passed, and there is an additional question, okay, why is it difficult to ask a hundred questions for this kind of question." ”

said with a smile: "Please ask Miss Ling Han to answer the question." ”

Ling Han thought for a moment and said: "I don't know the number of things, the remaining two of three or three, the remaining three of five or five, and the remaining three of seven and seven, may I ask what is the geometry of this number?" ”

At this time, Liu Fan even omitted to scratch the ground, almost without a pause, and immediately said: "Thirty-eight." ”

After listening to Liu Fan's words, the three people in the hall were once again stunned by Liu Fan's almost immediate answer.

Although Ling Han still looked incredulous, he paused slightly, slowly stood up and put his right hand on his left hand, increased his forehead with both hands, and said after making a long bow to Liu Fan: "General Liu, I was wrong just now, I saved a mind about testing your arithmetic ability, please forgive the little woman's presumptuousness, now I believe it, your calculation speed is not much better than that of the teacher." That's the case, after the teacher left, one day I got a problem, the initial calculation was regular, but after the number was greater than five, it was difficult to match the calculation results, so I asked General Liu to teach me. ”

After that, he bowed to Liu Fan with both hands and bowed: "Today, there is a lender with a hundred dollars, an annual interest of ten yuan, and five years to return it, how much is the interest?" Six years back, more geometric questions? ”

Listening to Ling Han ask the question again, Liu Fan knew that this is the problem that this girl really wants to help solve today, don't look at this question twice, but these five and six have deep meaning, this is the famous Yang Hui triangle problem in ancient China, Liu Fan vaguely remembered that Yang Hui was born in the Southern Song Dynasty, listening to the statement of this girl just now, it seems that Yang Hui Triangle has not yet appeared at this time, indicating that the research on Yang Hui Triangle in this era is only in the embryonic stage.

Newton said that his achievements were accomplished by standing on the shoulders of giants, and it seems that Yang Hui's trigonometry theory was also formed by the final continuous improvement of the research results of his predecessors, and was one of the important contributions of ancient Chinese mathematicians to the development of mathematics.

When Liu Fan was in college, because his major was closely related to mathematics, he had conducted a detailed study of the Yang Hui Triangle, and he could basically remember some characteristics of the Yang Hui Triangle, and the problem of five and six that the girl just said was one of the characteristics of the Yang Hui Triangle, that is, the first five elements of the Yang Hui Triangle were the zero to the fourth power of the eleven, and the law changed from the sixth line, and it seems that this girl has not found the corresponding law with the number eleven from the sixth line.

At this time, Liu Fan no longer bought anything, and said directly: "The interest in the fifth year is easy to calculate, because from the first year to the fifth year, the total principal and interest are one hundred times one point and one to the zero power, that is, one hundred." ”

As soon as he said this, Liu Fan saw Ling Han's frowning and puzzled look, and immediately explained: "This 'point one' means that the number behind this point is a micronumber. Ling Han immediately understood, and immediately nodded and motioned for Liu Fan to continue.

Liu Fan continued: "From the first year to the fifth year, the total principal and interest are one hundred times one point one to the power of zero, that is, one hundred, one square is one hundred and ten, the second square is one hundred and twenty-one, the third is one hundred and thirty-three points one, and the fourth power is one hundred and forty-six .forty-one, if these numbers are arranged from top to bottom, it forms a regular triangle composed of numbers, each number is the sum of the two numbers on its shoulder, and this law is broken in the sixth year, and the total principal and interest of the fifth year is one hundred and forty-six .41, And the sixth year is calculated according to the above law to be one hundred and sixty-one and fifty-one, and some of the numbers are no longer the sum of the numbers on their shoulders. ”

"That's ......"

After that, Liu Fan wrote down the Yang Hui triangle on the ground, first explained the number represented by these symbols on the ground, and then explained the law of the Yang Hui triangle to Ling Han in detail.

After listening to Liu Fan's explanation, although Ling Han felt very fresh and incredible that Liu Fan used these symbols to represent the numbers from zero to nine, she had basically understood the law of the number triangle explained by Liu Fan.

Li Shouyi and Li Min heard that Liu Fan immediately solved the problem raised by Ling Han, and saw Ling Han looking at the mess that Liu Fan had drawn on the ground, and at this time they also began to believe in Liu Fan's extraordinary ability in this arithmetic.

I only heard Li Shouyi say: "I know that Han'er's sister's arithmetic ability can't be said to be one or two in Daqi, but the third is definitely there, I didn't expect General Liu to have an in-depth study of this way, Han'er has been systematically studied under the guidance of a famous teacher since he was a child, and how General Liu learned these unfathomable abilities, this is really incredible!" ”

Liu Fan listened to Li Shouyi's words, and secretly scolded himself in his heart: "Fuck it, you really can't talk nonsense, don't you just want to borrow a few books to read, why is it that you are in a hurry to make others have serious suspicions, you must know how many lies it takes to get through!" ”

But at this time, Liu Fan couldn't help but give a reasonable explanation: "Alas, that's the case, I also told Li Lvshuai before, I like to think blindly since I was a child, when I was ten years old, I was playing with a small wooden stick at the door of my house as a calculation plan, and was accidentally seen by a traveling monk from the Western Regions who passed by, he asked me strangely what these small wooden sticks were for, I was also a teenager at that time, and immediately showed off in front of him, bragging about how good my arithmetic was, and even my aunt couldn't count me." ”

After listening to my words, Hu Seng smiled and asked me if I would like to have a competition with him. At that time, I was young and competitive, and of course I couldn't ask for him. ”

As a result, I compared three times in a row, and he had already given the answer as soon as I put the problem on the ground with a calculation chip, and I was amazed that I begged him to teach me the calculation method. In the end, he could not resist my hard work, so he told me about the symbols and the usage of these numbers, and when he left, he reluctantly left me a booklet, and said, 'Seeing that you are so studious, let me give you a good thing, and study it well, it will definitely benefit you a lot.' ’”

"The first half of the booklet is all about the arithmetic calculation method with these symbols, and I couldn't understand the latter at the time, but when I was a child, I had a good memory, and I actually wrote down all the content that seemed to make no sense at all.

Hearing this, I saw that Li Shouyi and Li Min both had a smile on their faces, but Ling Han, who was still studying Yang Hui's triangle next to him, stopped and listened to Liu Fan intently.

Unexpectedly, as soon as he said this, Dong Zi, who had been sitting in the back, asked suspiciously: "Brother, why don't I know these things!" ”

Liu Fan was digging out his mind to make up lies, completely forgetting that there was a stupid brother behind him.

Suddenly hearing Dong Zi speak, he was shocked, fortunately Liu Fan was still a little anxious, and quickly turned his head and glared, and said: "You ran behind Ah Hui's ass every day at that time, so you have time to pay attention to what your brother is doing!" ”

Today, when the two of them overheard about going home, they heard their younger brother say to themselves, 'I don't know how Ah Hui is now'. knows that although this younger brother is honest, he can't let go of his childhood playmates in his heart.

As soon as Dong Zi heard Liu Fan talk about Ah Hui, a rare twisted look appeared on his face that was not good at disguise, and he hurriedly bowed his head and said, "Oh." ”

I only heard Li Shouyi continue: "Brigade Commander Liu, is that book here with you now, can you borrow it from me?" ”

Liu Fan had no choice but to say in frustration: "I lost it early, when I was a child, I put that thing in my arms very much, I carried it in my arms every day, once I was playing in the water by the river, I couldn't put my books and clothes on the stones, I accidentally let the wind blow in the river, and when I found it, it had been washed away." After speaking, his face showed a look of full remorse.

After Liu Fan finished speaking, Li Shouyi and Li Min both had a look of pity on their faces, while Ling Han next to him had a pity on his face, and ordered the servants of the post house to bring paper and pen to draw the whole Yang Hui triangle that Liu Fan drew on the ground.