With a smile on his face, he seems to be a kind old man. It seems that people and animals are harmless, but Yang Xuan believes that as long as he shows a little intention to escape, he may face a thunderous attack.


    If he is alone, he can have a try and see the power of half step humanity, but don''t forget that there is a Meng Qingqing behind him at the moment.


    Meng Qingqing has been very clever and didn''t speak. Although she doesn''t know why Wudao will call Yang Xuan Mr. Ren, she knows that it''s the best choice to shut up at the moment.


    "Deference is better than obedience!" Yang Xuan bowed his hands as soon as he pondered.


    Making Wudao''s face showed a very gratifying expression, smiled and said, "it''s so good, Mr. Ren, please!"


    "Please!" Yang Xuan said.


    But for a moment, Yang Xuan came back to his hometown again. This time he didn''t have to sneak, but he still couldn''t see the whole picture of Biyun sect. It seemed that the whole valley was shrouded in a layer of fog.


    "Mr. Ren, please!" came to a hall and made Wudao fall down first and stand at the door.


    Yang Xuan also fell down with Meng Qingqing and entered the hall with no way.


    After the guests of honor took their seats, their servants served tea for the three.


    Ling Wudao looked at Yang Xuan and suddenly said with a smile: "Mr. Ren, to tell you the truth, there is also research on some logarithm, but it''s far worse than Mr. Ren."


    Yang Xuan couldn''t figure out what medicine he sold in the gourd. He smiled and said, "make the elder polite, count together, broad and profound. Ren is just a taste. It''s really not enough to mention."


    Ling Wudao laughed and said, "Mr. Ren doesn''t have to be modest. I''m really interested in the shadow measurement method proposed by Mr. Ren. I don''t know if Mr. Ren can answer one or two questions for me?"


    Yang Xuan''s heart was shocked and said in a secret way: here it is.


    At this time, he was also very curious. He didn''t know why Biyun sect was interested in this?


    However, he had told Zhang Heng and others about the knowledge of similar forms. It was really nothing. After a little meditation, he explained in detail some knowledge about similar forms in proportion for the sake of Wudao.


    After he finished speaking, he obviously saw that his face changed.


    The original face of Wudao was very flat, but now his face was full of uncontrollable excitement.


    "Mr. Ren, wait a moment. There is a man in Biyun sect who is a master of mathematics. I think he and Mr. Ren will be like old friends at first sight."


    After talking, he didn''t wait for Yang Xuan to answer, so he went out directly.


    At this time, Meng Qingqing and Yang Xuan were left in the hall. Meng Qingqing asked Yang Xuan with his eyes: what should I do?


    Yang Xuan shook his head and motioned Meng Qingqing to take it easy and act according to the circumstances.


    Although Meng Qingqing sometimes doesn''t tune very well, she also knows that they can''t help themselves at this time. She looks at Yang Xuan with sorry and her lips move slightly.


    With a little sweep, Yang Xuan knew what she said.


    Meng Qingqing said: you don''t have to save me.


    Yang Xuan smiled and shook his head, but said nothing.


    Meng Qingqing still wanted to talk, but suddenly shut up. The next moment, lingwudao had led a man in.


    This is an old man with messy hair. His eyes are deep set, his eyes are red, and the beard under his chin has stuck together. It seems that he hasn''t taken care of it for a long time.


    "Mr. Ren, this is my Biyun sect. Thank you, elder Xie. This is Mr. Ren."


    Yang Xuan''s heart was shocked, so that Wudao was already the deputy leader. Under one person and above ten thousand people, he could be called Xie Lao. Its importance is self-evident.


    He was acutely aware that this old Xie was probably a very important figure of Biyun sect.


    "The world is getting worse and worse. Any cat or dog can call you sir?" Xie Tianji blinked his small eyes, looked at Yang Xuan disdainfully, and then rushed to order Wudao to say, "you too, Wudao. How precious my time is. Do you have time to waste?"


    Wudao smiled awkwardly at Yang Xuan, and then said to Xie Tianji, "thank you, Mr. Ren is a great talent in the world. When will the moon be written by Mr. Ren?"


    Xie Tianji sneered: "it''s just playing with words. Since ancient times, writers and writers have not had a good thing. The better the literary talent, the less it is."


    Yang Xuan is a little speechless. The old man surnamed Xie really doesn''t like literati. Opening and closing his mouth is not something, but Yang Xuan is really not a literati. He is really wronged.


    Making Wudao helpless, he shook his head and said, "Mr. Xie, Mr. Ren also has deep attainments in mathematics. It must be helpful to Xie''s research."


    Xie Tianji was a little stunned, looked at Yang Xuan, and then sniffed: "numeracy is broad and profound. Can a cat and dog emerge casually, who can say he is proficient in numeracy?"


    He was speechless and looked at the stubborn old man a little helpless.


    Yang Xuan smiled and suddenly said, "it seems that old Xie has great attainments in numeracy. Ren wants to ask old Xie for advice."


    He has been keenly aware that the safety of him and Meng Qingqing may fall on the arrogant Xie Tianji.


    Xie Tianji looked at Yang Xuan with his nostrils and said, "do you want to teach me? Boy, you''re not qualified enough."


    Yang Xuan thought for a moment and suddenly said, "thank you, I have a question. Today, the wall is five feet thick. Two rats wear it side by side. The rat''s Day is one foot, the mouse''s Day is one foot, the rat''s Day is double, and the mouse''s Day is half. When will they meet? How do they wear it?"


    This is a question in the nine chapters of arithmetic, which means that two mice wear a five foot wall at the speed of one foot a day. The big mouse has great strength, and the speed is doubled every day. The little mouse is not strong enough, and the speed is halved every day. When can they meet and how many feet do they go through the wall?


    Xie Tianji was slightly stunned, then smiled and said, "this question is also interesting, but if you are only this level, it is just so."


    Then he squatted down and took out a piece of powder from his pocket and wrote it directly on the bluestone ground.


    After a long time, he stood up and said, "this question is also interesting. On two days of seventeen, the two rats met. The rats have eight feet through the wall and the mice have nine feet through the wall. I don''t know if my answer is right?"


    Meng Qingqing opened her eyes as if listening to the heavenly book. She understood every word spoken by Yang Xuan and Xie Tianji, but when they were connected together, she didn''t know what it meant. It was like listening to the heavenly book.


    Make Wudao a little better. After all, he heard Yang Xuan''s question clearly, but up to now, his mind is still a paste, not to mention solving the answer.


    Seeing Xie Tianji say the answer, the Taoist eyes immediately fell on Yang Xuan.


    Yang Xuan was awed.


    Even if he used modern methods to calculate this problem, it would take a lot of effort, but Xie Tianji drew some symbols on the ground that he didn''t know at all. It was incredible that he could get the correct answer in just a moment.


    At this time, he immediately understood that this is a rare mathematician in the world.


    Seeing Yang Xuan''s surprised face, Xie Tianji smiled proudly and said, "you can ask such mathematical problems. It seems that you really have some attainments in mathematical skills. In that case, listen to me."


    Xie Tianji opened his mouth and said, "now there is something that doesn''t know its number. Two is left out of three; three is left out of five; and two is left out of seven. How much is it?"


    Yang Xuan was a little stunned. He didn''t know the number of things? Something.