Chapter 293

In the National High School Mathematics League, the test questions mainly cover four mathematical branches: plane geometry, algebra, elementary number theory, and combination mathematics.

Of course, it is not just a mathematics competition, but also a test of these four aspects in the field of IMO. But this does not limit a certain type of problem to solve it with a certain aspect of knowledge. Mathematics is an internally interconnected subject. A problem can be solved by algebraic methods, and perhaps it can be solved by number theory. Mathematics is always full of infinite possibilities and endless fun.

For ordinary people, the formula that you think is too big may have a different aesthetic for this group of students participating in the competition and training.

…………

On the podium, Lao Tang held up a tutoring book and wrote down the topic on the blackboard first.

[Given the positive integer n, each of the six positive hexagons has a non-negative integer, and the sum of them is n. Now perform the following operation: erase a number on one, then write the absolute value of the difference between two adjacent upper numbers, and find all n, so that no matter which integers are at the beginning, a series of operations can be performed, so that each number on it is zero.]

Judging from the question, this question is not simple, and it is quite different from the various types of questions encountered in high school. No wonder, only one of the more than 30 people who participated in the training solved it.

Comrade Lao Tang was writing the steps on the blackboard while explaining to everyone below the stage.

He first drew a regular hexagon.

"First, according to the question, we assume that the parity of the six points of the hexagon is even, odd, odd, odd, odd, odd, odd, odd, odd, odd, odd, no matter how you operate, the parity of these six numbers will not change, then..."

"... According to the above process, we can temporarily draw a proposition: as long as the initial six numbers are not even, odd, odd, even, odd, odd, odd, and odd, then all numbers can be equal to zero through a finite number."

"This proposition is just written by ourselves, and we don't know whether it is true or false. Next, we need to prove that this proposition is a true proposition through classified discussion. Let's look at my discussion steps first..."

"...Did you understand the process on this blackboard? If you understand it, I will wipe it!... Next, we will discuss the situation of a2-a6=k. Since 0≤a2, a6≦k, we might as well set it..."

Crack Crack Crack Crack!

The two blackboards were wiped twice by Lao Tang, and dozens of lines of dense formulas were written. It took about half an hour before Lao Tang completed this question, which was extremely complicated in both the ideas and the process.

As for the students participating in the training stage, only two-thirds of the students are still confused.

Who am I? Where am I? Why should I attend this training?

After three confused companies, they all looked at the not-tall boy in the front row. His name is Chen Gong, and he has always been at the top of the age and is definitely a top student. He is also the only student among the more than 30 people who have solved this complicated problem.

Some people say that perhaps Chen Gong will be the second student to become the top scorer in the college entrance examination after Cheng Nuo, Qingcheng No. 2 Middle School.

The great god is the great god, it is indeed not comparable to our mortals!

Amid the eyes of everyone's admiration, Chen Gong's expression remained unchanged, and there was no expression of pride on his face.

To be honest, he only thinks this is just a very basic operation. Winning the first prize in the Several League, joining the national team, and winning the Imo gold medal is his goal in the future.

After talking for so long, Comrade Tang was also a little dry. He unscrewed the cap of the thermos cup on the podium, took a sip, supported the podium with both hands, and asked habitually, "Are there any questions about this question? If not, then we..."

Before Lao Tang finished speaking, he saw a hand slowly lifting up in the back of the classroom, and a slightly lazy voice echoed in the classroom, "Teacher, I have a problem."

Swish swish swish swish!

Looking at them in unison, the face that was reflected in their faces was a handsome but unfamiliar face.

However, Old Tang, who was standing on the podium, trembled when he saw the figure raising his hand in the back of the classroom, and then he couldn't help but shake his head and smile and scold, "Cheng Nuo, it turns out to be your boy."

Cheng Nuo?

The whole class was stunned for a few seconds, and then it became completely boiling.

Senior Cheng Nuo is a legendary existence of their Qingcheng No. 2 Middle School and the goal pursued by countless students. However, because Cheng Nuo's counterattack path was too short, the school has really seen it.

"Senior Cheng Nuo, it's Senior Cheng Nuo. I finally saw that I was alive!"

"So the senior is not the legendary loser. I think the senior has always been a fat man."

The two girls gathered together to chat and chatter, and their eyes looked at Cheng Nuo from time to time, but the content of the conversation made Cheng Nuo a black line.

The shadow of the tree. I have to say that Cheng Nuo's fame is indeed great enough at Qingcheng No. 2 Middle School. Some students may not know what the principal's name is, but everyone knows the legendary senior Cheng Nuo. Therefore, the classroom of Class 18 once became a place for competition training, part of the reason was to compete with Cheng Nuo, the immortal spirit of the college entrance examination mathematics.

The moment when Old Tang revealed Cheng Nuo's name, even Chen Gong Xueba, who had been sitting in the first row, turned his head suddenly and landed his gaze tightly on the boy who was not a few years older than him.

Is he...is Senior Cheng Nuo?

"Okay, everyone, calm down, quiet down." Comrade Lao Tang signaled everyone to quiet down, "Your Senior Cheng Nuo will hold a lecture in the auditorium of our school two days later. If you have any questions, you can save it until then."

Then, he said to Cheng Nuo, "You sit here for a while, and wait until I finish the last few questions to them, and then talk to you about the past."

Cheng Nuo nodded with a smile.

The classroom became quiet.

Comrade Lao Tang continued the previous question. He pointed to the blackboard and repeated the words just now, "Are there any questions about this question? If..."

In the back row, Cheng Nuo raised his hand again.

Old Tang was a little confused, "Cheng Nuo, I didn't say..."

Cheng Nuo smiled bitterly, "Teacher, I have no other meaning. But I have some opinions on the question you just mentioned."

Cheng Nuo's plain voice slowly echoed in the classroom.

Old Tang looked stunned. The familiar feeling in his memory emerged again.

Sure enough, Cheng Nuo was still the same Cheng Nuo, and it didn't change at all.

He motioned for Cheng Nuo to come up and cursed with a smile, "You are going to destroy the teacher's desk as soon as you come!"
Chapter completed!