492 years ago today, on May 3, 1533 (April 10, 1533 in the lunar calendar), Cheng Dawei, a businessman and abacus inventor in the Ming Dynasty, was born. Cheng Dawei, the father of abacus, Cheng Dawei (1533 ~ 1606) was a businessman and inventor of abacus in Ming Dynasty. Rusi, whose name is Binqu, Han nationality, was born in Lukou, Xiuning County, Anhui Province (now Tunxi, Huangshan City). When I was a teenager, I read widely, was interested in calligraphy and mathematics, and had never been an official in my life. Since the age of 20, he has been doing business in the middle and lower reaches of the Yangtze River. Because of the need of commercial calculation, he always pays attention to mathematics, visits famous teachers, collects many mathematics books, studies hard, and gains experience from time to time. When he was about 40 years old, he went home, concentrated on research, referred to various theories, and added his own opinions. At the age of 60, he completed his masterpiece "Pointing to Algorithm Tongzong" (referred to as "Algorithm Tongzong" for short). Cheng Dawei, the father of abacus, was born in a businessman's family on the 10th day of April, 12th year of Jiajing (May 3, 1533). Since childhood, he was intelligent and eager to learn. Because of commercial needs, he was very interested in mathematics. When he was young, he went out to do business with his father, traveled to Wu and Chu, and visited people and scholars. He met "elderly mathematics scholars, who made it difficult to visit and worked tirelessly." In order to realize his lofty ambition, he spared no expense to buy a suicide note. At the age of forty, he was tired of traveling abroad, so he abandoned his business and returned to his hometown, studied ancient books carefully, and extracted the strengths of famous scholars. After twenty years, he wrote seventeen volumes of the masterpiece Algorithm Tongzong in Renchen Year of Wanli, Ming Dynasty (1592). In the following six years, the book was simplified and written into four volumes of Compilation of Algorithms, which became the most basic reading book for later generations of folk calculators. Algorithm Synthesis details the traditional abacus rules, establishes the usage of abacus, perfects the abacus formula, collects 595 mathematical problems circulated in ancient times and records the solutions. It can be called a masterpiece of mathematics in China from 16th to 17th centuries. These two masterpieces are the most perfect abacus classics in ancient China, which ushered in a new era of abacus counting. At the end of the Ming Dynasty, the Japanese Maori was able to translate them into Japanese, setting a precedent for "harmony counting" in Japan. In the early Qing Dynasty, the book was introduced into Korea, Southeast Asia and Europe, and became a masterpiece of ancient oriental mathematics. Cheng Dawei, the father of abacus, the father of abacus, has 17 volumes in Algorithm Tongzong, which was engraved in the 20th year of Wanli (1592). The first two volumes talk about basic matters and algorithms, among which the formulas of abacus addition and division are the same as today's formulas. Multiplication is mainly based on "head-leaving multiplication", and division is mainly based on "return division", which has been used by later generations for a long time. Volumes 3 to 12 are a compilation of solutions to applied problems. Each volume is titled (Nine Chapters of Arithmetic), but "corn" is changed to "millet cloth" and "insufficient surplus" is renamed "surplus". Volume 3 "Fang Tian" chapter introduces his own "measuring walkway", which is made of bamboo grate and similar to a measuring tape. In Volume 6, the abacus algorithm of reducing and dividing squares and cubes is first proposed. Volumes 13 to 16 are compilations of "difficult problems", which are still classified according to nine chapters and expressed in the form of poetry. Volume 17 is "Miscellaneous Methods", which introduces the folk algorithm "Golden Cicada Escapes from the Shell" and the abacus calculation "One Stroke Brocade". In addition, there are "floor brocade", "palm of gold" (a finger algorithm) and various magic squares (i.e. vertical and horizontal diagrams), etc. Finally, the supplementary note "The Origin of Mathematics" lists various mathematical bibliographies since the seventh year of Yuanfeng in the Northern Song Dynasty (1084), with a total of 51 kinds, of which only 15 kinds are still biographical, and the rest are lost, but it is of great reference value for understanding the distribution of mathematical books at that time. Most of the 595 problems in Algorithm Tongzong are excerpted from other mathematical works, such as Liu Shilong's Nine Chapters of Tongming Algorithm (1424) and Wu Jing's Nine Chapters of Algorithm Comparison Encyclopedia (1450). The collection algorithm was relatively complete at that time, and it was a better one among similar abacus works at that time. In the development of ancient Chinese mathematics, Algorithm Tongzong is a very important work. It has spread widely and for a long time, and has played a great role in popularizing abacus among the people in China. At the end of the Ming Dynasty, it was also introduced to Korea, Japan and Southeast Asia, which also played an important role in spreading abacus in these places. Many mathematical problems in Algorithm Tongzong appear in the form of songs. Such as "Knowing the Monk with a Bowl" and so on. "Algorithm Tongzong" completely describes the "general song of positioning" of abacus positioning method for the first time: several positioning methods are strange, and they are all pushed downward because of multiplication. Addition and subtraction only need to recognize the standard position, and return to and divide the superior position. The method is more original and reverse to the upper number, and it is appropriate to get zero before the method. If the law is less original, the number will be reduced, and the law will get zero reverse knowledge before it. "In this book, Cheng Dazai absorbed the essence of various algorithms, but also accepted some wrong opinions. For example, the first book, "Revealing the River and Picturing Luo Book, Seeing the Number has its Origins", has the thought of digital mysticism, and at the end of the book, there is a nonsense song about estimating pregnancy and birth of men and women. In some places, the wrong formulas in traditional mathematics books are used, which are not corrected, resulting in false rumors. These have a bad influence on the later development of mathematics. In the twenty-sixth year of Wanli (1598), Cheng Dawei abridged Algorithm Tongzong, took its essential parts, and compiled it into four volumes of Algorithm Compilation, which were published in Tunxi successively with Algorithm Tongzong. Father of Tape Measure The world's first tape measure was invented by him around 1578. At that time, he called it "measuring walker", so Cheng Dawei was known as the "father of tape measure". Compared with today's steel tape measure and leather tape measure, the "measuring walker" is much larger, but from the perspective of its principle, structure, purpose and usage, it has to be admitted that it is the prototype of tape measure. It consists of wooden coat, cross, bamboo ruler, iron rotating center, drill foot and ring. The ruler is retracted and retracted from the plaque eye of the coat, the drill foot is convenient to accurately insert into the field measuring point, and the ring is convenient to carry. I curiously took it out and tried it out. Sure enough, the ruler can be retracted freely, and it is very convenient to measure, read and carry. What is even more rare is that the tape measure invented by Cheng Dawei not only has real objects, but also has a complete set of written materials such as parts drawings, final assembly drawings, design descriptions and modification descriptions in the third volume of Algorithm Tongzong compiled by Cheng Dawei, which is quite rare in the history of world inventions. The curator said: According to this set of information, woodworkers in any country in the world can easily copy it. According to the History of the Ming Dynasty, in the sixth year of Wanli of Emperor Shenzong of the Ming Dynasty (1578), Zhang Juzheng, the first assistant of the cabinet, ordered the whole country to clear the land, and took "land measurement" and "one-whip method" as important measures for his reform. It was learned from "Algorithm Tongzong" that Cheng Dawei personally participated in this large-scale land clearing work. Prior to this, "the ancient people measured the wider and long fields, and they all relied on rope rulers to pull them", which was not only labor-intensive, but also had a high error rate. Therefore, the inventor was put forward a subject, forcing him to think hard to create a brand-new measuring tool. He said in the design instructions that his idea came from the ink dogs used by woodworkers. The former residence of Cheng Dawei is located in the east of Shukou Canal, Tunxi District, Huangshan City, Anhui Province, covering an area of 540 square meters and was built in Zhengde period of Ming Dynasty. The main building of the mansion faces south, with three bays and two entrances (commonly known as "one ridge and two halls"), two floors, brick and wood structure, overhanging eaves inside and outside the gatehouse, curved beams and bucket arches, and horse-headed gables. On the west side is the ancestral worship building, with five bay rooms, built against the main building. At the entrance, a "Guest Garden" will be built, with antique cloisters, lawns and flower beds. The original artificial canal in Linbin Garden is called "Bingong Canal" by local descendants of Cheng family, and the official name "Bin Canal" comes from this. Cheng Dawei's former residence was built in Hongzhi period of Ming Dynasty and has a history of more than 500 years. Cheng Dawei's former residence covers an area of more than 4,000 square meters. It was officially opened to the public on September 18, 1986, the 380th anniversary of Cheng Dawei's death. The museum has a total collection of more than 4,000 literary and historical materials, and nearly 1,000 pieces of calculating tools of different shapes and functions (dozens of materials such as gold, silver, copper, iron, tin, stone, bone, ivory, clay, pottery, glass, plastic, seeds, sea pearls, etc.), fully demonstrating the historical process of the development and evolution of abacus, the fifth greatest invention in China. In particular, Mr. Cheng Dawei devoted his whole life to the writing "Direct Pointing to Algorithm Tongzong" and "Compilation of Algorithms", which created a new milestone in Chinese abacus. His book "Straight Pointing to Algorithm Tongzong" was written and published in May, 1592. This book has been widely circulated for more than 300 years, and spread to Japan in 1600, creating a precedent for Japan's peace calculation. Japan will hold a grand commemorative event every August 8th to commemorate Mr. Cheng Dawei. In the late Ming Dynasty, his books spread widely throughout Southeast Asia, Europe and America, laying the foundation for the development of abacus in the world. Extended reading: Tunxi Cheng Dawei Abacus Museum Extended reading: Tunxi Cheng Dawei Abacus Museum Dawei's former residence is located near the turntable in the center of Huangshan. It was founded in Hongzhi period of Ming Dynasty and has a history of 490 years. In 1985, to commemorate the 380th anniversary of Cheng's death, the former residence was renovated and opened, and the Cheng Dawei Memorial Hall was formally established, becoming an international abacus research and training center and a provincial cultural relics protection unit. Cheng Dawei (1533 ~ 1606), whose courtesy name is Ruen and whose name is Binqu, was born in Tunxi. He was a famous mathematician and abacus inventor in the Ming Dynasty. The former residence covers an area of 540 square meters. It was built in Zhengde period of Ming Dynasty. It is an ancient residential building in Huizhou in Ming Dynasty: horse head wall, white wall and tile, and cornices and cornices. The main building of the mansion faces south, with three bays and two entrances (commonly known as "one ridge and two halls"), two floors, brick and wood structure, overhanging eaves inside and outside the gatehouse, curved beams and bucket arches, and horse-headed gables. On the west side, the ancestral building, with five bay rooms, is built against the main building. The front hall is the living room, with a portrait of Cheng Dawei. The plaque of "Former Residence of Cheng Dawei" on the beam is inscribed by Professor Su Buqing, a famous mathematician. The hatchback is the house of Cheng Dawei and his family, and the west room is Cheng Dawei's original bedroom. On the west side of the former residence is "Binyuan", and Cheng's name is Binliang, hence the name. There are cloisters and paths in the garden, flowers and rocks, and elegant scenery. The walls and windows are all abacus patterns, which are not only distinctive, but also reflect the identity of the abacus master of the former residence owner, and are cleverly conceived. There is an abacus museum opposite the former residence, which displays all kinds of abacus, works of Cheng Dawei, genealogy of Cheng family and all kinds of abacus materials and pictures at home and abroad. On the left and right compartment walls are hung 10 life pictures of Cheng, such as "Teachers and Students Asking Difficulties", "Inviting to Tour Wu Chu", "Measuring Walkway" and "Military Thinking Above the Mouth". What is striking is the abacus of different shapes: the larger one has 81 gears and is 1.75 meters long; Small as a ring abacus, only 0.02 meters, has high ornamental value and cultural relics value. The big abacus is an over-the-counter abacus used by Tong Deren Pharmacy for the convenience of dispensing and calculation. Don't ask for help abacus and pendant abacus. This abacus looks ordinary at first glance. How can it be put in? Look carefully. This abacus is called "Twenty-Six Bead Abacus", and there are six grains under it. Double-waist linkage abacus, double-page three-in abacus, Jingangzi abacus, and ancient ancient calculus tools such as knotting rope notes, Taiyi calculation, gossip calculation, two instruments calculation, three talents calculation, nine palaces calculation, turtle calculation, etc., but they can't understand them all. It is estimated that mathematicians know. I couldn't see the positioning ruler invented by Cheng Dawei. It is said that it was borrowed to Huangshan Museum by the secretary of the municipal party committee himself (to tell you a joke. At that time, I pointed to the tape measure placed in the place marked with the positioning ruler in the display cabinet and exclaimed. This is the positioning ruler? How advanced! I was just about to sigh at Cheng Dawei's achievements. The administrator said that this is the tape measure, which was originally placed here to compare with the positioning ruler. I'm embarrassed)