"...To sum up, k is the square of a positive integer."

Using proof by contradiction to prove this question was not cumbersome and easy to understand, so Zhao Xiancai quickly finished explaining the question.

"I didn't mean to say, what group are you joining?

It stands to reason that for a question like this, which is considered very famous in previous IMOs, they should be able to find the answer easily, but why is it that no one in the group posted the answer?"

After finishing this question, Zhao Xiancai also asked Zheng Wenyi with some curiosity.

"The method of proof by contradiction is too powerful, and the solution process does not even use high school knowledge points.

If you look at it this way, it's exactly like a junior high school level of difficulty.

After reading the solution method you mentioned, I feel that this can all be included in the mathematics test paper of the high school entrance examination."

Ji Xinglei said from the side.

Zheng Wenyi, on the other hand, blushed a little at what Zhao Xiancai said, and ran back to her previous seat without answering Zhao Xiancai's question.

When Ji Xinglei just finished speaking, Zhang Jingqiang who was standing by said to him: "You have such a bad conscience.

For this IMO competition question, you actually said that you need to pass the high school entrance examination and let those junior high school students do it.

If those junior high school students heard this, I guess they would be eager to eat your flesh and drink your blood."

"Why is this broken? It is what it is.

This question is also simple. Can junior high school students understand it?

The process of proving by proof by contradiction does not require any high school knowledge, right?

Why can't it appear on the high school entrance examination papers?

Besides, it’s not me taking the high school entrance examination anyway.”

Ji Xinglei said cheerfully.

"Okay, Zhao Xiancai has finished explaining this question to you. Do you have any more questions to ask? If not, we will continue the class."

Seeing Ji Xinglei and Zhang Jingqiang bickering there, Lin Guangqiang said.

In fact, in the rest of the class, he was also giving lectures on topics, and others were also giving lectures on topics, but there was no difference.

Seeing that Zhao Xiancai continued to answer his questions and Ji Xinglei and the others did not ask any more questions, Lin Guangqiang continued the class.

After that, Zhao Xiancai spent the day reading papers and writing papers and talking about topics at night. September passed in the blink of an eye.

Next is the seven-day National Day holiday in October. In fact, for Zhao Xiancai now, it doesn't matter whether he has a holiday or not.

In the first half of the year, he could use more time to learn what he wanted to learn during the holidays.

But now even if there is no holiday, he can still learn what he wants to learn in class, and the teachers of each subject will not care about it at all.

This holiday is a good thing for Yu Shujun, because she can find opportunities to come to Zhao Xiancai's house and study with Zhao Xiancai.

"How do you feel about this monthly exam?"

Before the National Day holiday, they had just finished the first monthly exam for their sophomore year of high school.

Without the three subjects of geography, history and politics, their schedule for monthly exams is more generous and not as tight as before.

On the afternoon of the first day of the National Day holiday, when Zhao Xiancai sent Yu Shujun downstairs, he became concerned about her study situation again.

"I feel pretty good. I should be among the top ten in the class in this monthly exam." Yu Shujun said.

"You are already pretty good at math and physics, just keep it up.

That is biology, chemistry, Chinese and English. These subjects need to be improved.

I don’t have any learning methods for Chinese and English, so I can’t teach you anything.

But I have also taught you some of my biology and chemistry learning methods. In fact, they are similar to learning mathematics and physics, and the core is the same.

If you can raise chemistry and biology to a higher level, I think you can hope to get a '985' in the college entrance examination."

Zhao Xiancai said that what he said to Yu Shujun was exactly like the teachings of a teacher or an elder to students or juniors.

In fact, Zhao Xiancai said that Yu Shujun was able to achieve "985", which was also based on the fact that she not only had to mention chemistry and biology, but also Chinese and English.

But to encourage her, Zhao Xiancai only talked about chemistry and biology.

Judging from the admission rate of Chengxian No. 1 Middle School in previous years, there is usually one from Shuimu University or Peking University every year.

Since entering the 21st century, Chengxian No. 1 Middle School has experienced a situation that has not happened in Shuimu or Kyoto for three years.

As for the "985" schools, an average of four to five students per class can enter Chengxian No. 1 Middle School every year.

If we look at this data, Yu Shujun must at least be in the top five in her class and stay in the top five before she can attend a "985" college.

"Oh, I see."

Hearing what Zhao Xiancai said, Yu Shujun nodded solemnly as if she had been given another injection of blood.

Although Yu Shujun's attitude towards learning before was not bad, compared with now, it was as good as in the sky or on the ground.

In the past, when Yu Shujun came home from school, she would lie in bed and play with her mobile phone. How could she finish studying in the evening and continue to do homework and read books after returning home?

It can be said that Zhao Xiancai accounted for a large part of her current changes and her motivation to get up early and go to bed late to study.

Some people fall in love early and talk about getting pregnant and having an abortion while still in middle school.

And some people fall in love early, which can serve as motivation for each other to work hard to become better.

Even if it is unrequited love, if the person you have a crush on is very good, sometimes you will make the person you have a crush on become even better in order to get closer to your crush.

But there are also people who only feel that the person they have a crush on is too good and they are too bad, but nothing changes.

"Teacher Lin said that in previous years, the national mathematics winter camp for middle school students was held around December. If it was earlier, it might be in November, if it was later, it might be in January.

Therefore, I can only stay in school for another three months at most, or maybe just over a month at most. I may have to go to winter camp next month.

During this period, if you have any study questions, you can ask me more.

Although you can also contact me via mobile phone later, it is not as convenient as face-to-face.

I also hope you can get into a good university in the end."

Zhao Xiancai said.

The two of them had already gone downstairs, and Zhao Xiancai also took this opportunity to walk outside and relax.

He has been studying the questions for a whole day, so he can't stay bored in the room all the time.

"Yes." Yu Shujun nodded again and said to Zhao Xiancai, "If you go to college next year, will you come to school before summer vacation next year?"

“If I have time, definitely, but IMO competitions are usually in July, and I will definitely participate in training before July.

So when you come to school depends on the specific situation."

Zhao Xiancai explained.

After hearing Zhao Xiancai's explanation, Yu Shujun did not speak immediately.

After the two of them walked a few steps towards her home, Yu Shujun whispered: "Then... we can't appear in the same high school graduation photo."

High school graduation photos were all taken in the second semester of senior year. By the time Yu Shujun was promoted to the second semester of senior year, Zhao Xiancai had already graduated and was about to enter his sophomore year, so naturally he would not be in the graduation photos.

Regarding what Yu Shujun said, Zhao Xiancai didn't know what to say for a moment, so he didn't say anything at all.

"Huh? Are you Zhao Xiancai?"

Just as they walked downstairs to Yu Shujun's house in silence, a middle-aged woman happened to come downstairs.
Chapter completed!