After Qingshuang came in, she didn''t speak, but looked at Yang Xuan quietly.


    Yang Xuan was a little helpless and said, "are you so well informed? You came as soon as I came back."


    Qingshuang looked at him for a long time and said, "I opened this inn. What do you say, and I''ve been waiting for you here."


    Yang Xuan sat on the chair and poured himself a cup of tea: "what''s the matter? Ask me to go back and be a son-in-law?"


    Qingshuang frowned at him: "why did you do this?"


    Yang Xuan smiled: "nothing. I just feel that if I do this, I will suffer a little loss."


    Qingshuang''s face was full of speechless expression: "suffer a loss? Do you think it''s a loss to be a son-in-law? Qingxue''s national strength is several times that of Yan, and you have countless wealth. You become Qingxue''s son-in-law. In the future, when the princess ascends the throne and becomes emperor, you will be under one person and above ten thousand people, but you still feel a loss?"


    Yang Xuanpin took a sip of tea and said noncommittally, "the tea here is good."


    Qingshuang doesn''t understand what he means.


    Yang Xuan then said, "but I still like to drink some dark night fragrance. I''m used to it and can''t change my mouth."


    Qingshuang seems to understand what he means.


    "By the way, who has become the son-in-law?" Yang Xuan asked.


    "Yan Yixun, no matter what martial arts he learns, he will not be the second candidate except you." Qingshuang said.


    "Then don''t you hurry back and guard him?" Yang Xuan said casually.


    "Did I say I was a princess?" Qingshuang said faintly.


    "Whatever!" Yang Xuan shrugged, "what are you looking for me for?"


    Qingshuang looked at him again. She really didn''t know what the man was thinking. After a long time, she took out a simple ring.


    "Storage ring?" Yang Xuan was stunned.


    "Well, it''s a storage ring!" Qingshuang didn''t deny it.


    Yang Xuan smiled. The ending was really good. He didn''t have to be a son-in-law and got a storage ring.


    "Is it true or false to measure Zhou Zhi?" Qingshuang asked him for the last time.


    "Absolutely true." Yang Xuan answered directly without hesitation.


    Qingshuang threw the ring to him, then got up and went out. After walking a long way, she floated in and said, "you still owe a few days. Don''t forget to check out. Then, see you later!"


    Yang Xuan remembered that he only took out twenty liang of gold that day, which was only enough for one night, but now, I''m afraid it''s more than five or six days.


    "Really stingy!" Yang Xuan said helplessly, "see you later!"


    After saying that, he had looked at Zhang Heng who came in.


    Zhang hengchong and Yang Xuan hugged fist and said, "childe Ren, please explain the method."


    He didn''t point out Yang Xuan''s identity. It doesn''t matter. What he needs, or what Qingxue royal family needs, is just that method.


    Zhang Heng took the pen and paper, and Yang Xuan was not polite. After taking it directly, he drew a circle on the white paper, and then drew the diameter of the circle.


    His drawing ability is really not flattering. Not only is it round, but also the diameter is crooked.


    Zhang Heng frowned, grabbed the pen and paper and drew a circle again. It was like drawing with a circle. The straight line was also drawn with a ruler.


    Yang Xuan didn''t see any shame on his face. He explained it directly on the circle painted by Zhang Heng and played a guest role as a primary school teacher.


    "That''s it. I call this fixed number PI." Yang Xuan finished the explanation.


    Zhang Heng didn''t answer. He was thinking quietly. After a long time, he suddenly got up, bowed respectfully to Yang Xuan and said, "Sir, great talent, please accept my worship."


    Yang Xuan quickly helped Zhang Heng up. He blushed a little. He really deserved the worship.


    Zhang Heng got up and looked at Yang Xuan and sighed, "I didn''t expect that Mr. Zhang had such a deep research on numeracy. Compared with Mr. Zhang, I was really like a frog at the bottom of a well. I didn''t know it."


    Yang Xuan explained, "I''m just standing on the shoulders of my predecessors. It''s not worth mentioning."


    He explained in disguise, but Zhang Heng only thought he was modest. At this moment, Yang Xuan''s position in his heart reached a peak.


    Zhang Heng looked at Yang Xuan again and said with some embarrassment: "it''s reasonable that I should leave at this time, but I have a doubt in my heart. I''ve been confused for many years. I want to ask your husband to answer for me. What do you think?"


    Yang Xuan nodded. Anyway, he has nothing to do now. He has no loss to be a math teacher for Zhang Heng.


    Zhang Heng seemed very happy. He respectfully saluted Yang Xuan as a disciple, and then said, "have you studied the shape of the triangle?"


    Yang Xuan was stunned. Is this going to discuss trigonometric functions? He doesn''t know. He''s just afraid to say it. Zhang Heng doesn''t understand.


    "There are some studies!"


    Zhang Heng said happily, "that''s great. I have a question. It''s like this. Suppose there is a triangular object with straight sides and oblique sides. I know the length of any two sides. How do I know the length of the third side?"


    Yang Xuan breathed a sigh of relief. Isn''t this the Pythagorean theorem?


    However, when he really explained it to Zhang Heng, he really spent some time, because he had to turn the formula of Pythagorean theorem into mathematical knowledge of the world. In this way, it virtually increased the difficulty of explanation.


    He can''t directly tell Zhang Heng that a square plus b square equals C square. In that case, he has to be an English teacher. Even, he has to explain to Zhang Heng what square and root are.


    After a lot of talking, Zhang Heng finally understood.


    At this time, he was shocked by Yang Xuan.


    "Master, please be worshipped by the disciples!" while talking, he would kneel on the ground and kowtow to Yang Xuan.


    "Hey, what are you doing? Get up, it''s dirty... Oh, why don''t you listen?"


    It was not easy to pull Zhang Heng up. Zhang Heng''s attitude towards him was like seeing his own father.


    "Mr. Zhang has the kindness to teach his disciples. This worship will be a lesson for both heaven and earth." Zhang Heng said respectfully.


    Think about it, Yang xuanjiao gave him. Although in previous generations, it was only primary school or junior high school knowledge, the formation of these knowledge did not condense the efforts of predecessors.


    In fact, in Yang Xuan''s previous life, the more popular the knowledge is, the more classic it is. If it is spread one by one in this world, it will be absolutely shocking.


    Besides, take the multiplication formula learned in the second grade of primary school. If Yang Xuan teaches it, it will definitely cause great changes in science and Engineering in the world. At that time, Yang Xuan will be regarded as the existence of a Taoist ancestor and respected by the world.


    After Zhang Heng''s grateful departure, Yang Xuan had the time to study the storage ring that he almost sold himself in exchange for.


    When God swept away, he was already very happy.


    Although the space in the storage ring was small, only about the size of a bedroom, the strange fluctuations from the ring caught his attention when Yang Xuan''s mind was scanned.


    Why can there be space in the ring? This is what he is thinking now.


    Can he simulate this fluctuation with aura? If so, does it mean that he can open up his own space without relying on the storage ring.


    He was also a little excited at the thought.


    However, after careful study, he always felt that something was missing, which interrupted his thinking for a time.


    He put the things in his arms into the ring, and then watched them appear in his hands. He had a lot of fun. This strange feeling is really wonderful.


    The next day, he went directly to the counter to return the room.


    Of course, he settled the expenses he owed very readily. He wouldn''t let Qingshuang see a joke for this.


    After leaving the Inn and making a circle outside the city, he regained his true colors.


    Back at Meng Qingqing''s house, he first refined some Huitian pills, then thought about it, and refined more weight-loss pills.


    After a while here, Meng Qingqing came again.


    "Are you hurt?" Yang Xuan''s face sank when he saw Meng Qingqing''s first eye.