Liu Meng's question came out, everyone took out a pen and paper to calculate, although Liu Meng just said that thinking is the most important, but in the case of time constraints, students are still used to starting to calculate, this is the influence of the mindset, in fact, this question is like 1+2+3 has been added to 100 questions, it is very easy to find the right entry point.

Time passed quickly, and a minute passed immediately, Liu Meng asked with a smile: "I don't know if any classmates have got the answer?" The students at the scene reacted at this time, and they haven't figured out the situation yet, where can there be any results, Liu Meng didn't hope that someone could do it, and suddenly a small hand was raised, and it was the skinny classmate before, Liu Meng was quite surprised, and said: "Does this classmate know the answer?"

The skinny little student stood up and said, "Of course, this is a series summation problem. But it has another ingenious solution: since the two cars are 200 kilometers apart and travel 50 kilometers per hour, it takes them two hours before they collide. So, the fly flies for 2 hours, so it must have traveled 150 kilometers. As Professor Liu said, it will be very simple to think differently and calculate the flight time instead of calculating the distance traveled by flies step by step. ”

Liu Meng was very surprised, he didn't expect that there were really classmates in Surabaya No. 1 Middle School who reacted so quickly, and couldn't help asking: "Completely correct, what's your name?"

This classmate said shyly: "My name is Ji Bin, and I am in the third class of the second year of high school." ”

"Well, sit down, very well, if you keep your interest in mathematics all the time, you will be a great mathematician in the future. Liu Meng spoke highly of it. He continued: "Legend has it that at a dinner party, a young man met von Neumann and asked him this question. Von Neumann pondered for a few seconds before replying: Oh. 150 km, of course. The young man was shocked slightly, thinking that Teacher Feng was really good, so he patted his ass. 'Ah, Teacher Feng is really clever, and he immediately thought of the method of multiplying time by the speed of flies. Von Neumann replied, "What? I asked for the sum of the series." ”

After Liu Meng told a little joke, the students in the audience laughed.

This time the speech was over, and the students surrounded Liu Meng and refused to go back to the classroom. asked any questions, and many female classmates looked at Liu Meng with admiration, and felt that this big brother who was not a few years older was too powerful. Profound knowledge, as well as the maturity of self-confidence and experience, attracted the girls at this stage, I don't know who started it, everyone took out their notebooks and asked Professor Liu to sign them. Liu Meng did not refuse. Write some words of encouragement to everyone's notebook, this trouble, Liu Meng was able to get out half an hour after the speech ended, and returned to the Mammoth Science and Technology Building next to Surabaya No. 1 Middle School.

That night, Liu Meng was alone in the conjecture where Goldbach had been stuck, when the doorman came to inform him that a classmate had asked to see him, saying that his name was Ji Bin, and Liu Meng was very impressed by the student. Just let him in, and Ji Bin came to Liu Meng's study. I saw that it was full of all kinds of mathematics books, which were arranged according to Mr. Kong's house at the beginning, which was convenient for reference.

"Sit down. Liu Meng smiled very kindly, and after Ji Bin sat down, he was still curious to look around, and he hadn't seen so many mathematics classics at once, "Xiao Ji, is there anything wrong with me?"

Ji Bin was a little nervous and took out a few sheets of A4 paper, but these papers were not the kind of regular printing paper, but there was a small shop in the north of Surabaya No. 1 Middle School that specialized in buying that kind of large paper...... I really tried to solve the Goldbach conjecture, and you said that if you have an idea, I will come to you, I ...... I'm here. ”

Liu Meng saw that he didn't seem to be joking, and his heart was shocked at the moment, wouldn't it? A sophomore in high school solved the problem of being stuck in the world for more than a hundred years in one afternoon? At the moment, he couldn't wait to look at it, Ji Bin was a little embarrassed, "I just calculated according to my own understanding, and I don't know if it's right." Liu Meng thought to himself that if this was right, he would still have it, although his heart vibrate, he hoped that he could really solve it, and he had fulfilled his promise to Teacher Kong.

"Elementary mathematics proved?" Liu Meng couldn't help but speak out just after looking at it twice, he hadn't thought about it in the past, the reason was that it was impossible to prove this conjecture with elementary mathematical methods, and higher mathematical tools must be used, but after a brief look, although this method was primitive, there was no problem for a while.

I saw that the original two forms of Goldbach's conjecture were written crookedly on the paper: (1) any even number not less than 6 can be expressed as the sum of two odd prime numbers, such as 6=3+3, 8=5+3, 10=7+3, 12=7+5, etc. (2) Any odd number not less than 9 can be expressed as the sum of three odd prime numbers. For example, 9 = 3 + 3 + 3, 11 = 3 + 3 + 5, 13 = 3 + 5 + 5, etc.

The writing is very simple, even Liu Meng doesn't doubt it, is it really so simple?

Ji Bin saw that Liu Meng's brows were furrowed, and said nervously: "When I was eating at noon, I suddenly thought that I could use the double-number sieve method to prove the 1+1 problem of Goldbach's conjecture in the field of elementary mathematics. ”

Liu Meng was about to go crazy, he really didn't see any mistakes after watching it for the first time, his thinking was very clear and complete, although it looked really simple, he couldn't help but look at it seriously.

"Let N be any even number not less than 6: 6, 8, 10......N, and Xn be any positive integer not greater than N/2: 1, 2, 3...... N/2, then N can be expressed as the sum of N/2 pairs of positive integers: 1+(N-1), 2+(N-2), 3+(N-3)...... N/2+N/2, expressed by the formula: N=Xn+(N-Xn);In this N/2 logarithm, each pair contains two additions, if one of the two additions in each logarithm is a composite number or 1, the number pair in which it is located must be removed, then what remains is the number pair containing only prime numbers, we let the number of such prime pairs be n, then as long as it is proved that when N≥No there is n≥1, Goldbach's conjecture (1) is true......"

Liu Meng couldn't help but tap his fingers on the table, his face gradually became solemn, and after reading it again and thinking about it for a while, he was a little disappointed, sighed and said: "When I read it for the first time, I really thought that I would use this method to solve the conjecture simply, and when I read it again, I found that you just gave a few examples of satisfying the conditions in the article, this method can indeed solve most of the numbers, but the simplest numbers such as 9 and 144 do not meet your proof conditions, what is the most difficult thing about Goldbach's conjecture, do you know?"

Ji Bin couldn't say a disappointed face, a young man, always full of passion and fantasy, shook his head.

"The most difficult part is that this is a proof that all infinite integers are true, and such a method is untenable, even if there is no untrue number found within tens of billions, but how can we ensure that there is no untrue situation in the subsequent infinite numbers? Once discovered, the whole proof method is overturned. ”

Ji Bin nodded sadly.

Seeing his sad appearance, Liu Meng knew that he was a little harsh in his speech, and said with a smile: "Although you haven't really solved the conjecture, you have proven your mathematical talent, you can come to my study room in the future, even when I am not in Surabaya, you can ask me if you have any questions." "This is already cultivating Ji Bin as a student, and under the influence of Teacher Kong, Liu Meng's mind is also much broader, and the height he stands at is also different.

Ji Bin thought about it and nodded.

After Ji Bin left, Liu Meng took the steps written on the paper and thought about it, although these steps were wrong, but Liu Meng also broke through the previous mindset, Goldbach guessed whether it was possible to solve it through guò elementary mathematics, or whether one of the steps could be transformed through guò elementary mathematics? You must know that the essence of mathematics is actually in elementary mathematics, and advanced mathematics is just a means, because the philosophy contained in elementary mathematics is the most testing of thinking ability, such as how to make a regular seventeen-sided shape with a ruler, which requires genius thinking, which is also Euler's most proud work.

Liu Meng still remembers that when he was in elementary school, there was an old scholar in the same village, who often liked to come up with some questions for children to do, there was such a question at that time, about an old lady carrying a basket of eggs to the market to sell, but accidentally knocked down by a hawker on horseback, the egg broke to the ground, then the vendor had to compensate the old lady, the old lady was afraid that she counted the wrong number, so she counted the eggs repeatedly, one by one counted the last egg, two two piles were left in the end, three or three piles were still left, four or four piles were left in the end, and five or five were left in the pile, six or six piles are still one left, so how many eggs are in this basket?

At that time, in addition to Liu Meng sitting next to him, there was also a junior high school student and two high school students, junior high school students heard this question and immediately thought of writing multiple equations to solve, high school students thought of using quadratic equations, or even cubic equations, all of them were settling with a sad face, and Liu Meng, who was only in primary school at the time, quickly gave the answer, the reason is that he has not learned any equations in primary school, but he does not know any complex equations at all, he uses the principle of least common multiple in primary school.

Thinking of the anecdote when he was a child, Liu Meng couldn't help but smile, because of this he was labeled a genius in the village, and the old man who asked the question concluded that Liu Meng would definitely do a lot in the future.

Liu Meng lay down and closed his eyes and pondered, can elementary mathematics solve difficult problems? Goldbach's conjecture is a problem that elementary school students can understand, but could it be that mathematicians are too difficult to see? Thinking of this possibility, Liu Meng decided to try, all the methods of advanced mathematics, and even the creation of a randomly distributed deterministic field by himself failed to solve the problem, so why not go back to the basics and try it? (To be continued......