The carpenter came soon, a black-faced man in his forties, who was still wearing clothes, at least much better than Chen Xu's family before. And when he met the newly appointed Lord Lidian for the first time, he was a little nervous and nervous.

"The craftsman Liu Erwa has met Lord Lidian!"

Chen Xu's legs became weak and almost went upstairs. An old man was called Erwa.

"No gifts, I have designed a new calculation plan, please help me create it!" Chen Xu pulled the carpenter's arm to the front of the stone slab, and explained the structure of the abacus and the size of each component in detail, "Do you understand?"

"I understand, I understand!" The carpenter nodded repeatedly. Although he had never seen the abacus, he was a professional carpenter recognized by Daqin. After all, he knew how to do it with a simple structure.

"Because time is urgent, just use bamboo to make it. The faster the better. Can it be done in an hour?" Chen Xu breathed a sigh of relief.

"It doesn't take an hour, half an hour!" The carpenter nodded easily.

"That's good, go and do it!" Chen Xu waved his hand, and the carpenter quickly bowed and left.

"Sir, how should I use this plan?" Niu Quan stared at the abacus pattern on the stone slab and stared at it for a long time before asking suspiciously.

"Don't worry, I'll think about the mantra first!"

Chen Xu squatted down again, picked up a piece of charcoal and started writing and painting on the stone slab, muttering, "One, one, two, two, four, one, two, eight, one, seven, two, two, two, two, two, two, go... go... go... go... go... go... go... go... go... go... "

Chen Xu wrote a long row of messy Arabic numerals like chanting scriptures, and kept pulling his hair down with strands.

Niu Dashi was no longer surprised by the words Chen Xu wrote, which seemed to be crickets, and he could recognize a few of them, but Niu Quan was completely confused, but he did not dare to disturb Chen Xu. He could only stand behind him with his eyes wide open like reading a heavenly book.

Chen Xu learned the abacus formula when he was a child, but it was limited to addition and subtraction. Moreover, a decade or twenty years have passed, and it has long been regressed and returned to zero in memory.

But even so, as a great national treasure, after his slowly recalling, more than ten minutes passed, and the simple addition formula was still made by him. He could just get the abacus and then dial it out next to each other.

Subtraction is a little more troublesome, but with the addition formula, it can still be deduced. As for multiplication and division, that... is really too difficult. It can't be summarized in just a few months, and it's not available at the moment.

An hour passed quickly, and Chen Xu's subtraction formula was almost straightened out. At this time, the carpenter ran over with something panting.

"Sir, the plan is done!"

"Very good!" Chen Xu stood up happily, but then there was a black look in front of him and almost hit the stone slab. His body shook a few times and was quickly supported by Niu Dashi.

Damn it took me a long time to squat and feel a little anemia.

Looking at the bamboo abacus two feet long and one foot wide, Chen Xu picked it up and shook it a few times, then used his fingers to thrust the abacus beads made of bamboo joints. Although there were some burrs and lags, they basically met the requirements.

"Niu Quan, I will teach you how to use this calculation sheet. Remember these tips!"

Chen Xu said as he placed the abacus on the stone slab, pointing to the eight wooden blocks above and said: "This first represents a single digit, the second represents ten digits, the third represents a hundred digits, and so on, the remaining one represents a thousand, ten thousand..., the four beads below represent one, two, three, and four, and the bead above represents five, then one is one, and the formula is called one, one, the upper one..."

Chen Xu said as he pushed a single bead up with a bang.

"Two means two, the mantra is called two and two..."

Chen Xu said as he moved his fingers, and with the crackling sound, the numbers from one to nine were demonstrated one after another.

"Now start the addition operation, one plus one, one plus two... If you spend five, then the next one goes to four..."

The addition of abacus is actually very simple, just remember the formulas carefully.

With Chen Xu's explanation and demonstration, Niu Quan was stunned when he heard this, his mouth wide open, and his eyes widened.

He is also proficient in superficial mathematical addition and subtraction. He usually uses calculation sheets to count addition and subtraction, but he does not feel complicated. However, when he saw the new calculation sheet designed by Chen Xu, he felt like he was overturning while memorizing the formula.

"Niu Quan, come and try it!" Chen Xu stood up and pointed at the abacus.

"Okay, let me come down and try it!" Niu Quan squatted down excitedly, pursing the formula while pulling the abacus beads. Chen Xu guided and reminded him that after more than ten minutes, Niu Quan was able to apply the addition in full. Although it was slower, there was basically no error.

"Okay, take out the tax grain list you received yesterday and calculate it to see if there are any errors!" Chen Xu ordered.

"Hey, okay!" Niu Quan quickly went to the warehouse to take out a roll of bamboo slips, spread them on the stone slab, and began to accumulate and settle according to the numbers recorded on each bamboo slip. In just a few minutes, Niu Quan's face turned red with excitement: "Master Lidian, the data between the two are not bad at all. This calculation is really magical and convenient. In the future, you can bring a cart to collect grain in the village... Uh, sir, can this calculation be named Chen's calculation!"

"No, just call it abacus!"

"Okay, calculate the data, count the correct and wrong, and make the abacus just right!" Niu Quan quickly flattered.

Chen Xu silently contempted a few seconds in his heart for the mathematician who invented the abacus hundreds of years later. I'm sorry for that ancestor... Well, it's not right. Before I came here, I should be their ancestor.

"The abacus is light and easy to use, but you must remember the formulas in your heart. There are subtraction formulas later. You can use them skillfully. If you don't understand, please ask me. I will ask the carpenter to create a few more abacuses to send them. When the grain collection team comes back, you will teach the tax servants to use them. No mistakes can occur in the matter of summer grain!"

"Don't worry, Niu Quan will save money!" Niu Quan nodded quickly.

Chen Xu then told the carpenter to make a few more bamboo abacus, and at the same time asked him to use wood to create a more beautiful and exquisite one. When he was fine, he could calculate the multiplication and division formula. He recommended it to the county magistrate Jiangbeiting in a few days, and maybe he could get some benefits.

Soon, several days passed. As the threshers in various villages began to be manufactured in large quantities, the news reported by several pavilions that the harvesting of summer grain had entered a very good state, and the grain collection team also kept pulling piles of grain to the warehouse every day.
Chapter completed!