Wanderer of the whirling world

Chapter 5 Calculations
When he was drowsy, Xin Ziqiu seemed to have returned to Beijing Yanyuan, staying in his dormitory, sitting in front of the newly bought computer.

He continued happily eating shrimp crackers, playing games, commanding his little dwarf mage, hiding behind the boss and throwing spells.

They beat the Red Dragon BOSS in one fell swoop, and the team channel was full of laughter...

The boss even sang a song with a hoarse voice, Dou Wei's "Longer Tomorrow":
"Farewell to the night and wait for the dawn.

Past glory no longer matters,
Tomorrow will be longer..."

This feeling was so real that Xin Ziqiu even felt that all the weird experiences just now seemed to be just a bizarre nightmare.

……

Just when he was like a butterfly in Zhuang Zhou's dream, he couldn't tell which was reality and which was illusion, when he heard a thunderstorm not far from his ears, which was deafening.

He woke up in a jerk, opened his eyes suddenly, stood up, and looked around.

I saw that I was in a ruined temple at this time, with overgrown weeds and uneven lengths.

There is a Buddha statue more than three feet high in the temple. Its head is gone, and the golden body of the clay sculpture is also mottled, with most of the paint peeled off, and dark green moss growing everywhere.

It was already night at this time, and the outside of the ruined temple was pitch black with heavy wind and rain.

Showers came, thunder and lightning flashed, and the raindrops hit the eaves of the temple like a bead, making a rattling sound.

Not far from him, there was a bonfire, and Jia Xian, his grandfather and grandson, were sitting next to the fire.

The girl in red, Jia Zhiqing, turned her back to him, with her head lowered, as if she was playing with something on the ground.

The old man Jia Xian was holding a pancake in his mouth, and looked at his granddaughter with a smile, his face full of pampering.

Xin Ziqiu sighed, feeling a little disappointed that he was still trapped in this dangerous world after all.

Hearing a voice here, Jia Xian glanced over and found that Xin Ziqiu had woken up, so he stroked his beard and smiled:

"Little friend woke up? The old man was negligent just now, and didn't realize that you have been injured by the Gu corpse, and the corpse poison entered your body. But the poisoning is not deep, I have applied medicine to you, you may be a little dizzy for the past two days, it's nothing serious .”

Xin Ziqiu looked down at his wrist, only to see that it was wrapped with thick cloth.

I don't know what kind of medicine Jia Xian used, but the numb and itchy feeling has disappeared, replaced by a piece of coolness, and there is a faint fragrance, which is refreshing.

At the same time, he also found that he had actually changed into a long coat and trousers made of coarse cloth.

Although the clothes are a bit short and don't fit well, and the fabric is rough and stiff, making them uncomfortable to wear, at least they are decently warmer than the previous vest and shorts.

Seeing him staring blankly at his clothes, Jia Xian laughed again:

"Oh, seeing how naked you are, I was afraid that you would catch a cold. This old man made his own decision and changed you into my clean clothes. I hope you don't dislike me."

Xin Ziqiu felt warm in his heart, and felt warm kindness for the first time since time travel.

It seems that no matter which world it is in, there are more good people in the end.

He stood up, bowed deeply to Jia Xianzu and his grandson, and said sincerely:
"Thank you both for saving your life, Xin Ziqiu is very grateful."

Jia Xian smiled and said:

"It's nothing to do with a little effort. You have been asleep for two or three hours, you must be hungry. Come and eat something, but there is nothing delicious, only cooking biscuits."

The girl in red, Jia Zhiqing, also turned around and said with a chuckle:
"It turns out that your name is Xin Ziqiu, and you fainted before you finished reporting your name."

Xin Ziqiu smiled awkwardly, no need to ask, the scene just now must have been extremely embarrassing.

When he first came to this world, he had many doubts and questions in his heart.

where is this place?
In which direction is Bianliang City in Tokyo?

What exactly is the "Sutra of the Underworld" that he was looking for on the parchment, and where can I find it?

After finally meeting Jia Xian and Jia Zhiqing's grandfather and grandson, they both seemed to be good people, so he was about to inquire about them one by one.

So he walked to the side of the fire and sat down next to Jia Xian. He was about to speak when he saw a lot of delicate bamboo pieces scattered all over the ground. He immediately became interested and put aside the question he had just thought about. .

I saw that these bamboo slices were seven or eight centimeters long, two or three millimeters thick, each one was exactly the same, with patterns engraved on them, not to mention expensive, but very exquisite.

Jia Zhiqing placed these bamboo slices on the ground, some horizontally and some vertically, neatly arranged, and she concentrated on her own thoughts, staring at the ground with her beautiful eyes, concentrating on it.

Xin Ziqiu took a look and immediately understood what she was doing.

These rows of regularly arranged bamboo slices are exactly the counting chips used for counting.

Counting chips, also known as operators, are tools used by the ancients to do decimal calculations.

Although these small bamboo pieces are inconspicuous, they contain great wisdom of the ancient Chinese working people.

Counting chips can not only be used for counting, but also can be used for addition, subtraction, multiplication and division, and can even be used for multiplication and square root calculations. It has a wide range of uses and basically covers all the calculation needs required by ancient people for production and labor.

Although Xin Ziqiu knows little about ancient Chinese history, he has been interested in mathematics since he was a child, and he has also been deeply involved in the history of mathematics in China and the West.

Whether it is abacus or arithmetic chips, he has worked hard to study it, and even won an award for abacus and mental arithmetic when he was a child.

At this time, he clicked his counting chip and saw that Jia Zhiqing was using the "increase multiplication method" to calculate the cube root of 530.

He was very excited, knowing that this old man who had just saved his life was probably, as he had guessed, the famous mathematician Jia Xian himself in the Northern Song Dynasty.

The "increase multiplication method" was proposed by Jia Xian. In theory, it can calculate the square root of any power of a large number, and it is more procedural. It is one of the representative achievements of ancient Chinese mathematics, which is better than that invented by European mathematicians. Similar prescribing procedures are more than 700 years earlier.

Not only that, the famous "Jia Xian's Triangle" is also one of his main contributions, and was later quoted and promoted by Yang Hui, a mathematician in the Southern Song Dynasty, which is almost 600 years earlier than the "Pascal's Triangle" in the West.

It is a pity that many works of this great mathematician have not been passed down to the world, which is really a great pity.

Xin Ziqiu looked at Jia Xian with admiration in his eyes. Although these simple mathematical ideas are nothing in the 21st century, many middle school students can understand them, but this is the Northern Song Dynasty 1000 years ago.

Jia Xian's ability to jump out of ordinary people's cognition and propose new methods and ideas far beyond that era is really admirable.

He looked at the counting chip on the ground again, and the method of multiplying and opening formed a fixed procedure for the method of cubic opening, which was systematic, standardized, and easy to promote.

It's just that this method is a bit cumbersome and has many steps.

Jia Zhiqing was concentrating on thinking, constantly fiddled with calculations, and was not sloppy at all.

Xin Ziqiu's mental arithmetic skills are extremely strong, and he has mastered this kind of elementary number theory topics in elementary school.

To solve this kind of problem, modern mathematics has some tricky methods, but it is not applicable to all numbers.

For example, for the current question, using the method of decomposing prime factors, he immediately calculated that the answer is 170.

At this time, Jia Zhiqing had just counted as "one" in the hundreds.

It was a bit complicated when it reached the tenth place. Jia Zhiqing fiddled with the calculations for a while, calculated a "six", and wrote it down on the ground with a charcoal pencil.

Xin Ziqiu saw that she had miscalculated, and coughed slightly.

Jia Zhiqing heard Xin Ziqiu's unnatural coughing, raised her head and glanced at him, thought about it, and decided to do the calculation again.

Now I calculated a "seven" in the tens digit, so I crossed out the "six" just now and wrote it down again.

Then he couldn't help but glance at Xin Ziqiu again, with a bit of doubt and surprise in his eyes.

(End of this chapter)