"My nephew, please see my aunt!" The pink and handsome little boy Li Chengdao bowed and saluted Princess Pingyang.

"Dao'er, why are you here today?" Princess Pingyang also walked over in surprise and helped him up and said. It was the first time she had seen Li Chengdao since the last birthday party. She also knew that Li Chengdao was busy with his studies and had almost no time to go out, so when she heard him visiting her, she was very surprised.

"It's a coincidence. Wang Fu took me out to observe the river situation near Chang'an these days. I happened to observe the Huangqu today. After my nephew completed his studies, he asked Wang Fu to visit his aunt. Wang Fu also agreed!" Li Chengdao also replied with a smile.

Don’t think that the daily education of the prince and grandson is to study hard. In fact, the ancient elite education they received was very comprehensive, which is more similar to the quality education in later generations. Especially for those like Li Chengdao who are likely to inherit the throne in the future, they must also understand astronomy, geography, military and other knowledge while studying, otherwise how can they be a good emperor?

"So Daoer, you have already started learning geography, but do you have any experience?" Princess Pingyang was also very concerned about Li Chengdao's studies and asked with a smile.

"I have some experience, but there are many questions, and even several Wang Fu can't answer them." Li Chengdao replied obediently. He is a child who likes to think independently. After learning a lot from the teacher, he will also add to his own thinking. But it is precisely because of this that he has more questions than other children, and sometimes even his teacher cannot answer them.

"Oh? What are the questions?" Princess Pingyang asked curiously when she heard this. She knew that Li Chengdao was an extremely smart child and had many knowledgeable masters taught him. What questions were there that they could not answer?

"I have reported to my aunt and nephew who has been studying the situation of the Yellow River during this period. Ancient books say that the Yellow River is the longest river in my Central Plains, but no one knows how long it is. In addition, I heard some officials from the south say that the length of the Yangtze River in the south is also very amazing and is definitely not below the Yellow River. So my nephew really wants to know which is the longest, the Yangtze River or the Yellow River?"

Li Chengdao immediately explained the puzzle in his mind, but Princess Pingyang was stunned when she heard his words. She had never thought about how long the Yellow River was. As for the Yangtze River, she had heard of it. It is said that the basin spans east and west, and it seemed that it was not under the Yellow River. However, which of these two lines was longer, even she had never thought about this problem.

"Aunt, do you think which is longer, the Yangtze River or the Yellow River?" Li Chengdao asked again at this time. He seemed to know that it was a bit difficult to ask the length of the Yellow River. After all, unless you have measured it personally, it would be impossible for others to know.

"This..." Princess Pingyang didn't know how to answer this question for a while, but soon she had a flash of inspiration, "I really don't know about this question, but my aunt knew that there was someone who must know it!"

"Who is it? Auntie quickly call him to help her nephew answer it!" Li Chengdao's eyes lit up when he heard this. He was not only precocious, but also had a stronger desire for knowledge than ordinary children. These two questions have been tormenting him for several days.

"That's not possible. If you ask others for advice, you must make a gesture of asking for advice. Moreover, this person is so knowledgeable that he only saw in his aunt's life. If you have any problems in the future, you can come and ask him for advice. Never be as rude as last time!" Princess Pingyang reminded him with a serious look on her face.

"Last time?" Li Chengdao was stunned at first, and then guessed who Princess Pingyang was talking about. He said suddenly, "My aunt is talking about Li Xiu, but he is so young, is he really as knowledgeable as you said?"

"Although Li Jijiu is young, you will know how powerful he is then!" Princess Pingyang did not explain too much, and stood up with a smile. Li Chengdao was also curious at this time. He followed Princess Pingyang out of the villa and walked straight towards Li Xiu.

Li Xiu's new home is closer to the Princess's Villa, but it's just a moment's time. When Princess Pingyang entered the yard, she saw Yue Chan commanding several maids to work. When she saw her, she immediately stepped forward and saluted, "I will see the princess!"

"No need to be polite, is Li Jijiu at home?" Princess Pingyang asked gently. After not seeing her for a while, she also found that Yue Chan in front of her had lost a lot of weight and became more beautiful, but this also made her feel a little worried.

"Princess Qibing, the master went out this morning. After just coming back, he took Qi Niang into the inner house. He has not come out yet. Do you need a servant to go in and report it?" Yue Chan replied respectfully.

"Well, there is no need to inform you, just go in!" Princess Pingyang has come many times and is very familiar with Li Xiu's home, so there is no need to inform you at all. She took Li Chengdao to the inner house and soon heard the laughter of Li Xiu and his brother and sister from the small garden, which also made Princess Pingyang smile slightly.

Princess Pingyang took Li Chengdao into the garden and saw Li Xiu and Qi Niang on the grass at a glance. However, Princess Pingyang was stunned at this time because there was a strange thing on Li Xiu and Qi Niang's faces, which actually covered their eyes. The two were looking around, and Qi Niang even laughed from time to time.

"Hey, princess, why are you here?" Li Xiu soon saw Princess Pingyang at the entrance of the garden. He ran over excitedly and said, "The glasses on his face were too late to take off. This was made by him using some colored crystals for craftsmen to grind them. In addition, there are some other gadgets. He was playing with these things with Qi Niang just now.

"Li Jijiu, what are you wearing on your face?" Princess Pingyang asked in surprise when she saw the glasses on Li Xiu's face.

"Haha, this is glasses, which are used for shading light, and of course it can also be used as a decoration!" Li Xiu said as he took off the glasses on his eyes, and then helped Princess Pingyang put them on with his own hands. As a result, Princess Pingyang immediately discovered that the world in front of him was dyed blue suddenly, and the originally dazzling sunlight became softer.

"Haha~, the princess is so beautiful with these glasses. Of course, if she adds a sun hat and lies in a bikini on the beach, she will be even more beautiful!" Li Xiu immediately exclaimed. The glasses were designed according to the style of later generations, and then asked a master craftsman to create them. Although the details are a bit unsatisfactory, the general appearance looks similar to those of later generations.

"What is a bikini?" Princess Pingyang asked in confusion when she heard this. She could barely understand the sun hat. It should be a blocking sun, but this was the first time she heard of the name bikini.

"Well~, a kind of clothes are very beautiful. I must give them to the princess if I have the chance in the future!" Li Xiu said evilly. He estimated that if Princess Pingyang knew what a bikini was, she would probably kill him with one knife. After all, women of this era were still too conservative.

"Auntie!" At this moment, Li Chengdao, who had been ignored, suddenly spoke up to express his dissatisfaction. After all, as soon as he saw him, Li Xiu had been chatting with Princess Pingyang and completely ignored him, Prince Anlu, which made him a little angry.

"Huh? Why is Prince Anlu coming too?" Li Xiu had just noticed that there was a child beside Princess Pingyang, which made him surprised. He had only paid attention to Princess Pingyang just now, and he did not notice Li Chengdao.

"Haha, Dao'er came to visit me today. He had a few academic problems and couldn't figure it out, so I couldn't answer them, so I brought him to ask Li Jijiu for advice!" Princess Pingyang finally remembered this nephew and said embarrassedly.

"So that's it. I wonder if the prince has any questions to ask for advice?" Li Xiu said guiltily when he heard this. He was worried that if Li Chengdao asked him what poems, songs and essays and various schools of thought, it would be not difficult for him to steal a few poems, but if he was asked to talk about the knowledge in poetry, it would be difficult for him, such a person who could not even memorize the Analects of Confucius.

Li Chengdao Bingxue was smart. He could not help but sneer from Li Xiu's expression. He didn't help but sneer at the moment, and did not give Li Xiu any hope. However, for the sake of his aunt, he still raised his questions about the Yellow River and the Yangtze River.

When Li Xiu heard that Li Chengdao was asking which Yangtze River or the Yellow River was longer, he couldn't help but breathe a sigh of relief, and the expression on his face became very confident: "I didn't expect that the prince would learn from it and be able to put forward his own ideas under the teacher's explanation. As for which Yellow River or the Yangtze River is longer, I can tell the prince with certainty that the Yangtze River is slightly longer than the Yellow River!"

"Really?" Li Chengdao did not expect that Li Xiu would answer his question, but he still said with some doubts, because he was worried that Li Xiu would not know at all, but he told a random answer for the sake of face. Anyway, no one could prove that he was lying.

"Of course it's true. If I remember correctly, the length of the Yangtze River and the Yellow River is more than ten thousand miles, but the Yangtze River grows more than one thousand miles than the Yellow River!" Li Xiu replied with a smile. He couldn't remember the specific length of the Yangtze River and the Yellow River, but he knew that both rivers exceeded 5,000 kilometers, which is more than ten thousand miles.

"So the Yangtze River and the Yellow River are so long!" Princess Pingyang couldn't help but sigh when she heard Li Xiu's words. Ten thousand miles is a very long distance. She has fought in the south and north over the years, and I don't know if she has walked ten thousand miles together?

"Haha~, princess, don't be surprised. In our Central Plains, the Yangtze River and the Yellow River are indeed the two longest rivers, but for the world we live in, they are not the longest rivers. For example, the Yangtze River can only rank third in the world, and there are two other rivers longer than it!"

As men, they like to show themselves in front of their beloved women, and Li Xiu is no exception. However, his words aroused Li Chengdao's curiosity and asked anxiously: "Li Jijiu, don't know what rivers are?" (To be continued.)
Chapter completed!