In the Silver Empire, the four-year quarterly reconciliation table was announced. When the local shopkeeper listens to the reimbursement, what algorithm is used under the table?

Roughly the same as when I was a child, snapping my fingers to add, subtract, multiply and divide! But people have their own set, and the numbers represented by ten fingers have all been said.

But it also belongs to the mental arithmetic class in quick calculation!

Want to know more, look at this material!

In the CCTV hit drama "Walking to the West", tofu flower praised Ching Tien Association for its quick calculation of "swallowing gold in the sleeve" many times. (that is, you don't need an abacus for calculation)! So what is the speed algorithm of swallowing gold in the sleeve?

Swallowing gold in the sleeve is a quick calculation method and a numerical calculation method invented by ancient businessmen in China. The sleeves of ancient clothes were hypertrophy, and only two hands were in the sleeves when calculating, which was called swallowing gold in the sleeves. There used to be a ballad about this calculation method; "Swallowing gold on the sleeve is as wonderful as a fairy, and the number of fingers is moving. You learn priceless treasures, but your bosom friends don't pass them on."

The algorithm of swallowing gold in the sleeve is a folk palm calculation method. Businessmen in China do math, while Shanxi businessmen do accounts while walking. Ten fingers are an abacus, so Shanxi people always swallow a pair of hands in their sleeves for fear of revealing his economic secrets. In the past, in order to make a living, people would not easily spread the secret of this algorithm, and a fast calculation method called "swallowing gold in the sleeve", which has been circulating in China for at least 400 years, is also on the verge of extinction.

According to relevant data, in A.D. 1573, a scholar named Xu Xinlu wrote a book "The Pearl Plate Algorithm", which first described the rapid calculation of swallowing gold into the sleeve; In A.D. 1592, a mathematician named Cheng Dawei published a book, Algorithm Planning, which described the swallowing of gold in the sleeve in detail for the first time. Later, merchants, especially Shanxi merchants, popularized this ancient quick calculation method. The algorithm of "swallowing gold in the sleeve" is a stunt of Shanxi's bank secrecy, and some big merchants and shopkeepers in xi 'an know this fast algorithm.

The method of quickly calculating numbers by swallowing gold into the sleeve is to use five fingers of the left hand as the digital dial, each finger represents a number, and five fingers can represent five numbers: one, ten, hundred, thousand and ten thousand. The upper, middle and lower segments of each finger respectively represent the number 1-9. Arrange three numbers on each section, and the arrangement rules are divided into three columns: left, middle and right. Fingers are arranged upside down on the left (from bottom to top), 1, 2, 3; Fingers are arranged upside down (from top to bottom) in the middle, 4, 5, 6; Fingers are arranged upside down, 7, 8, 9. The calculation method of swallowing gold in the sleeve is a method of using mental arithmetic to reproduce the calculation process with the image of the brain and get the result. It regards the left hand as a virtual abacus with five gears, and clicks the virtual abacus with the right hand to calculate. When counting, point the fingers of your left hand with the fingers of your right hand. Its clear division of labor is: right thumb/left thumb, right index finger, left middle finger, right ring finger, left ring finger and right little finger. The corresponding professional division of labor does not interfere with each other. Which finger is clicked, which finger is extended, and which finger is not clicked, bending, indicating 0. It doesn't need any calculation tools, and it doesn't list arithmetic programs. It only needs to close two hands gently to know the answer number, and can perform four operations of addition, subtraction, multiplication and division on any number within100000 digits.

The operation speed of' swallowing gold in the sleeve' is comparable to that of an electronic computer (of course, it takes some time to practice), multiplication and division are faster than abacus calculation, and square calculation is much faster than pen calculation. Although for beginners, using' swallowing gold in the sleeve' to calculate simple data is not as fast as a calculator, after mastering this skill, the calculation speed is even faster than a calculator. Someone once calculated the speed of the' swallowing gold in the sleeve' algorithm. A person skilled in this skill will get a 3-to 4-digit multiplication result, which takes about 2 seconds. The result is 5 to 7 digits, about 7 seconds;

Although the algorithm of swallowing gold into the sleeve is born out of abacus, compared with abacus, it does not need any tools, only uses one pair of hands. Because it has the characteristics of "swallowing gold in the sleeve" without tools and eyes, it is very suitable for field work and can also be used in the dark, especially for the blind, and some problems can be solved through this algorithm. "As the saying goes,' ten fingers are connected to one heart', training calculation skills with fingers can exercise bones and muscles, and clever thinking can promote the mind and improve brain power.