After the Mid-Autumn Festival, the busy disaster relief work was carried out in turn, and all the prefectures and counties that had been infested by locusts were opened to release grain, and daily statistics were collected. All prefectures and counties carry out cross-inspections to check whether there is any phenomenon of fraudulent occupation and forcible occupation.

The statistics were not reported once every ten days, and the Ministry of Civil Affairs (the Ministry of Households, which had been called so during the Zhenguan period and was not changed until Li Zhi took the throne) agreed to verify the grain consumption in various places, and then distributed it uniformly through Caoyun.

Throughout the disaster relief process, Li Chengqian's name was mentioned countless times, and the reason was simple - Arabic numerals were too easy to use.

The data of dozens of state capitals are gathered together, which is definitely not a small number, and a large amount of calculation work is simply a nightmare for those officials who calculate it if it is counted in the previous way.

Even now, with the convenience of Arabic numerals, a large number of calculus can be a lot of calculations.

"His Royal Highness the Prince, think of a way, the minister is really tired to death in this way." Li Jingxuan, the new leader of the Dushui Prison, took a sip of the tea handed by Li Chengqian, and said with a bitter face.

"What's the matter? Running around the world with the old horse didn't tire you like this. Li Chengqian joked with a smile.

"Don't mention it." Li Jingxuan sighed and said: "There are many problems with the data sent by the Ministry of Civil Affairs, and there are often some calculation errors, so every time the minister has to personally check the ......."

"Do you count yourself? Such a large amount of data, you count it alone? Looking at Li Jingxuan's somewhat blue eyes, Li Chengqian said with some surprise.

"Yes, fortunately, those data are reported every ten days, and there is still some room for effort, otherwise the minister really doesn't have to sleep." Li Jingxuan said with a wilt, it seemed that he could fall asleep at any time.

Poor guy, if Li Chengqian doesn't help him again, it is estimated that the future prime minister of the Tang Dynasty will soon die of overwork.

"You go to the back and sleep well first, and when you wake up, this palace will give you a good thing." The hard-pressed subordinates finally reminded the prince of a calculation tool that was almost on par with the four great inventions—the abacus.

There are different opinions about abacus in modern times, some people say that it existed in the Eastern Han Dynasty, some people say that it originated in the Tang Dynasty and was popular in the Song Dynasty, and some people say that it only arose in the Yuan Dynasty.

Now, Li Chengqian can confidently tell those historians that the abacus appeared in the Tang Dynasty.

forcibly ordered Li Jingxuan to rest, Li Chengqian arranged for Wu Chen to go to the street to grab a carpenter at random, the abacus is a simple thing to make, even the carpenter apprentice can do it, and it is not a confidential thing, there is no need to keep it secret at all.

A large frame, with a partition in the middle, seventeen thinner small round wooden sticks are arranged on it, and seven beads are strung on each stick, separated by the partition, two on the top and five on the bottom.

For more than an hour, a plan with the fragrance of wood was freshly baked, except that it was not lacquered and a little frizzy, everything was so perfect.

Sending the carpenter away, Wu Chen approached Li Chengqian, looked at the abacus curiously, and poked it a few times with his hand: "Your Highness, what is this?" ”

"Something that can make Li Jingxuan sleep well." Li Chengqian tried hard to recall the abacus mantra and replied casually.

"Sleep in your arms?" Wu Chen asked with a snort.

"Roll the calf, do you report that you are sleeping with an abacus, hurry up and grind it." glanced at Wu Chen, who took ignorance as amusement, with disdain.

An addition and subtraction formula, a multiplication and division formula, and an abacus, this is what Li Jingxuan saw after waking up.

Li Jingxuan's heart was touched by Li Chengqian's behavior of leaving alone without waking him up, and his heart was warm, although the young prince deceived him, he believed that it was out of kindness.

But soon his attention was drawn to what was on the table, and he took the instructions of the abacus and looked twice, and then tried to fiddle with them a few times according to the addition of the verbal decision.

The movements of his fingers were still a little clumsy, and the speed of calculation was a line slower than that of his hand calculations, but Li Jingxuan was still stunned.

Although the speed of calculation is not as good as hand calculation, Li Jingxuan understands that it is because he is not proficient, and if he is familiar with it in the future, then the speed of calculation can be faster.

After repeated attempts, Li Jingxuan's calculation speed with the abacus soon surpassed that of hand calculation, and the speed continued to accelerate with the improvement of proficiency.

Almost unconsciously, the data of a state capital has been checked, and looking up at the time, Li Jingxuan was stunned to find that it only took half of the usual time.

Excited, ecstatic, Li Jingxuan didn't know how to describe his mood, he was not sleepy after just sleeping, so he simply took the account books of another state capital and continued to check.

The data of one state capital after another was constantly checked, and when the time came to the second half of the night, Li Jingxuan, who was excited, simply woke up a colleague who had already slept.

One of them read according to the account book, and the other kept fiddling with his fingers on the abacus, and just like that, the sound of 'crackling' rang all night.

When it was dawn, the sound of 'crackling' playing with abacus beads finally stopped, and Li Jingxuan and his colleague Mu Ran looked at each other in the quiet room.

The account books were gone, and in one night, all the account books were checked.

Looking at the abacus placed on the table, Li Jingxuan almost wanted to put it on the shrine and offer it.

This is a special artifact, and it is completely an artifact used for calculation!

A large number of calculations have been difficult problems since ancient times, and Li Jingxuan was also worried, so he really had no choice but to complain to Li Chengqian, and deep down he didn't expect to really have any good solutions.

But what I never expected was that in just half a day, a useful and simple magic calculation tool had appeared in front of me, and it seemed that this thing could not be described by a calculation tool.

Li Chengqian's various rumors have spread widely in Chang'an City, such as 'poetry and poetry' and 'wisdom demons', which are even more cocooned to people's ears.

Li Jingxuan and Li Chengqian have also been in contact several times, and he doesn't think that this prince is really as magical as the rumors, and even thought that these rumors are some things to catch the wind and shadows.

But now Li Jingxuan, who has been fiddling with the abacus all night, has been convinced, and he has been completely convinced, and in just one afternoon, he can make such a magical thing, so as to solve the calculation problem that has caused countless literati in the Tang Dynasty to have a headache, from this point of view alone, the rumors about the prince in Chang'an City seem to be a little superficial.

Working under such a magical prince, Li Jingxuan felt honored, or his lofty ambitions would definitely be able to be displayed under his hands, and the emotion in his heart turned into a kind of fanaticism, a kind of fanatical worship of the 'strong'.