Since entering Donghua Xianmen, Xu Yi has been diligent in his practice, and has not let go of reading and appreciating various rules and regulations of Donghua Xianmen.

This jade plaque engraved with the word "Dian", as soon as Fang appeared, Xu Yi recognized it as a forbidden card of the Classic Pavilion.

Donghua Xianmen has two major classic libraries, one is the Gongfa Building that collects the world's exercises, and the other is the Classic Pavilion.

Compared with the Gongfa Building, the status of the Classic Pavilion is only high, not low.

It is only because in the Classic Pavilion, in addition to not containing the largest number of exercises, there are various classics, among which there are a small number of Dan prescriptions and extremely rare runes.

And this library of classics will also not be simply open to the outside world, if you want to borrow it, you must either consume merit points, or use the classic card, which is the jade card thrown by Elder Bai at this moment.

According to Xu Yi's knowledge, this kind of classic card is only issued to the level of immortal monarch and elder, if there is no merit, each immortal monarch and elder only has three borrowing opportunities every year, and the number of times cannot be accumulated.

This kind of classic card is too crucial for Xu Yi at the moment.

Elder Bai said, "You can take it, this thing is placed here by Lao Tzu, it has not been touched for decades, Lao Tzu is still too busy to study the exercises, how can he have time to take care of it." There is only one point, you kid have a little conscience and hand over all the delicious food in your Sumeru ring to Lao Tzu. ”

Xu Yicai accepted the card, hearing this, he couldn't help but feel a pain in his heart, he was a glutton, and the treasures collected in the Sumeru ring were all the delicacies in the world, if they were all searched by Elder Bai, it would be tantamount to a catastrophe for him.

As soon as the thought moved, he had an idea, and at the moment, he stacked the piles of bottles and cans, and said with a bitter face, "That's all, if the seniors still want it, the juniors will help the seniors Zhang Luo." ”

What he took out at this moment, although it was extremely large, was only one-tenth of the inventory in his Sumeru vows.

Even if it was only one-tenth, Elder Bai was speechless, he really had never seen a monk use the Sumeru ring like this, this time it was an eye-opener.

After receiving Xu Yi's filial piety, Elder Bai threw out two booklets and asked Xu Yi to study well, but he moved the shabby rattan chair to a corner of the sun and fell asleep.

Half an hour later, Xu Yi finished reading the two booklets, and he was a little unclear.

What is recorded in the two booklets is a discussion about a kind of number technique, and it is obvious that the content of these two books is selected from a single exercise.

Among them, the key "Great Derivation Number Theory" and "Heavenly Mystery Xuantu" are extremely profound, as intelligent as Xu Yi, and they can only be seen in the clouds for a while.

In the final analysis, his research on mathematics only stays at the stage of extreme foundation, or in other words, his research is purely based on utilitarianism.

Whether it is Guiyuan Step or Zangfeng Style, he is only limited to understanding the core of mathematics, and is not willing to diverge at all, and even systematically studies what kind of ocean of mathematics is after the extension of its core.

At this moment, it is reasonable that he cannot comprehend the "Great Derivation Number Theory" and "Heavenly Machine".

Elder Bai's sleep did not last long, and when he woke up, his spirit was restored, and Xu was in a mood of sustenance, which made his whole person look less irritable and more gentle.

Elder Bai didn't talk nonsense, pulled Xu Yi over, and asked him to carefully explain what kind of mystery was hidden in the hidden front style.

Xu Yi had already prepared, and at that moment, he calculated for Elder Bai in the hall.

He was amazed to find that it was much easier for him to teach Elder Bai again than last time.

Obviously, for the rest of the month, Elder Bai was not wasted.

At the same time, it also gave Xu Yi some insights in his heart: diligence can make up for clumsiness, no matter how bad the qualifications are, find the right direction, and work hard, you can eventually achieve success.

After nearly two hours of calculations, Elder Bai basically figured out the Zangfeng Style, this time, he was not busy immersed in the deduction of the Zangfeng Style, and suddenly threw a Sumeru ring at Xu Yi, and hummed, "I see that your kid knows the way of mathematics is extremely limited, and I think it is like those mediocre talents, who only regard the study of mathematics as a skill, but do not base it on it." ”

"It's just empty Baoshan and don't know, there are some mathematical studies in the Sumeru ring, you take it and understand it, go back to Lao Tzu to test you, if you don't pass the assessment, what Lao Tzu gave you, you kid have to give Lao Tzu back. ”

When it comes to this, Xu Yi can only agree.

Now, Elder Bai seems to have become the thickest and strongest golden thigh in his Donghua Immortal Sect, even if it is a dead skin, he has to hold it tightly.

The thought invaded the Sumeru Ring, Xu Yi was stunned, where are there some, there are so many of them, there are hundreds of them, and they are full of three bookshelves.

Xu Yi exclaimed, "Seniors, even if the juniors are talented, these ......"

Elder Bai waved his hand, "I don't listen to the others, I hope that in seven days, you can finish the Dongcao Sutra and tell me the scriptures." ”

But he said in his heart, "It's easy to find a coolie, how can Lao Tzu let it go so easily, you kid is unlucky, no, serve Lao Tzu, it should be your kid who creates ......"

It turned out that the classics of mathematics that Elder Bai gave to Xu Yi were all the essence of the world's kneading techniques, among which there were foundations and high-level theories, all of which were carefully selected by Elder Bai's organization.

The "Dongcao Sutra" that Elder Bai said in a suitable way is part of the basic arithmetic techniques.

He deliberately stipulated that Xu Yi should study the "Dongcao Sutra" first, where was it for Xu Yi, but for him to think about himself.

Elder Bai's idea was to ask Xu Yi to learn first, and then teach himself.

He found that it was really difficult to learn mathematics, and although he did not lack the perseverance of the foolish man to move mountains, he always regretted it sometimes.

After Xu Yi twice talked about the subtleties of Guiyuan Step and Zangfeng, Elder Bai suddenly found that it was really time-consuming and laborious to study on his own, and if he let others study thoroughly, he would undoubtedly save a lot of labor and effort by passing on it to himself.

Obviously, Wang Qianqiu, who was the initiator, was targeted by Elder Bai when he pushed the boat down the river.

Elder Ping Subai said that "the number of techniques is close to the avenue", Xu Yi heard it, and felt quite reasonable.

But if he really wants to spend all his time studying mathematics, Xu Yi is absolutely unwilling, he really doesn't have that spare time.

Mathematics is close to the avenue, who is willing to study who goes, anyway, he is impatient.

However, at this moment, he had no room to refuse, Elder Bai was not a good man, he really believed that if he dared to refuse, as soon as this old man went crazy, he really had no good fruit.

Helpless, he had no choice but to respond, and made up his mind to take a look at it for a while, if he really couldn't wait, only here he didn't have a place to stay with his master.

Xu Yi agreed, Elder Bai, who was obsessed with the study of mathematics, of course he didn't have time to spend time with him, so he sent him out.

Xu Yi took the classic card and went straight to the classic pavilion.