The door of the room was pushed open by Liu Cheng, and Liu Cheng smiled and made a gesture of please to Cai Yan.

After Cai Yan saluted Liu Cheng, he walked towards the room.

Liu Cheng then entered and closed the door of the room......

……

……

In the room, Cai Yongzheng put away the pen from a piece of paper, held the paper with both hands, and respectfully handed the paper to Liu Shui on the side: "Xiaoyou, check it to see if there are any mistakes in my calculations?" ”

Liu Shui took the paper handed over by Cai Yong and began to look at it meticulously.

Cai Yong stood aside, focusing on the paper Liu Shui was holding, and watched intently as Liu Shui checked what he had written.

Even, Cai Yan can see some nervousness on his father's face, for fear that something will go wrong.

Such a scene, Cai Yan was dumbfounded.

I just feel that my brain, which has always been smarter, is useless.

What is this?!

Yesterday evening, what the person who went up from the Emperor's Mansion said was true?

His own father is really here to follow the disciple he just accepted to do learning?!

This......

It's shocking!

Cai Yan didn't know how to describe his mood for a while.

Liu Cheng on the side, looking at the side of him who was so surprised that he couldn't help but open his mouth wide, and he could see some white teeth Cai Yan, only to feel that his heart itched even more.

He regretted a little that he didn't seize the perfect opportunity to lead Cai Yan to another room just now, but led him to the study.

Of course, thinking like this in his heart, Liu Cheng still knows the severity of the matter.

A person's day, I don't know how many thoughts will come up, and I really put them into action, not even a tenth......

"Ah, grandpa, you, you ......"

After being stunned for a while, Cai Yan finally spoke.

It's just that Cai Yan, who has always been articulate, can't even say a word at this time.

Cai Yong, who was waiting for Liu Shui intently and checking his calculation steps, couldn't help but feel a thrill when he heard the words, and was taken aback.

It was not until this time that Cai Yong and Liu Shui discovered that they didn't know when, there were actually two more people in this room.

"Akihime? How did you get here? ”

Cai Yong looked at Cai Yan and was stunned for a while, then he reacted and asked loudly.

"Grandpa, are you really doing arithmetic?"

Cai Yan did not answer Cai Yong's question, but opened his mouth to ask like this, and directly stepped forward a few steps to see the paper in Liu Shui's hand.

Now, after seeing such a scene with her own eyes, the curiosity in Cai Yan's heart almost burst her chest.

Of course, this also has something to do with the fact that her chest is relatively flat, not wide and majestic enough, and the corresponding volume is relatively small......

Cai Yan, as a very famous talented woman in history, in addition to her literary attainments, she also understands arithmetic, after all, her father has a lot of experience in arithmetic.

She wanted to see what kind of title was written on this paper, and she was able to fascinate her father like this!

His eyes fell on the paper that Liu Shui was holding, and after seeing clearly what you wrote on the paper, Cai Yan was suddenly even more confused.

Because she found that she couldn't understand the question!

Not only the title, but everything that was densely written on the paper, she couldn't understand......

The famous talented woman in history swept her eyes over the faces of several people in the room one by one, and then fell back to the piece of paper in Liu Shui's hand, and for a while, she couldn't say a word......

……

……

"These are Arabic numerals, and this method of calculation is called vertical calculation, and these are the ...... that my brother taught me."

Liu Shui opened his mouth again to explain.

"These things, I have never seen them before, and I have never heard of them, the most rare thing, is so easy to use!

Uncle Huang, how do you know these things? ”

Cai Yan looked at Liu Cheng, his eyes full of exploration.

As soon as Liu Cheng was about to speak and explain, he heard a voice on the side: "My brother said that this was before, my uncle saved a Hu Shang, and this is the Hu Shang professor to his uncle, and the uncle thought it was useful, so after the brother grew up, he gave these professors to the brother."

The elder brother said that his uncle had not allowed his brother to spread the word about this matter before.

On the one hand, this way of calculation, as well as the way the numbers are written, is different from our common words, and we are worried that if it is revealed, it will cause trouble for ourselves.

On the other hand, because this thing does have its advantages, my uncle is going to pass it on as a family heirloom......"

Liu Cheng closed his mouth and stood here with Cai Yan to listen to Liu Shui tell him nonsense about Liu Shui.

Sometimes, in some things, it is really a headache to meet some children.

When Cai Yan heard Liu Shui's story, he set his eyes on Liu Cheng on the side, and looked extremely surprised.

This kind of thing that I haven't seen at all, but it's very mysterious, it seems to have a systematic arithmetic, and it actually comes from the hands of this fierce general who can compete with Lu Bu on this side?

"Unintentionally, I saw the unpassed learning of the emperor's uncle's family, and the little woman ......"

After Cai Yan reacted, he hurriedly apologized to Liu Cheng.

People in these years are still very particular about learning, especially family learning.

"Senior sister doesn't have to be like this, my brother said that knowledge is used for use, and many things are because many people cherish themselves and only want to pass on their children and grandchildren, so they finally declined.

Only by teaching more people and carrying it forward can we make a knowledge give full play to its true value.

Only then can we concentrate everyone's wisdom and make this knowledge better and more novel, and it will not be annihilated in history......"

Cai Yan stood in place and was stunned.

After a while, she bowed deeply to Liu Cheng, who wanted to speak, but couldn't interject for a while......