1. Definition of upper bead and lower bead: An abacus usually consists of a frame, a beam, beads and a file. The upper bead refers to the bead on the beam, usually located in the middle and upper part of the abacus, and the lower bead refers to the bead below the abacus, usually located in the middle and left side of the abacus.
2. Representative numbers of the upper and lower beads: In the traditional abacus, each file usually represents a number. The upper bead represents the number 5, and the lower bead represents the number 1. Therefore, when an upper bead and a lower bead appear in a file at the same time, they represent the number 6.
3. Calculation method of upper and lower beads: On the abacus, the upper and lower beads can be combined to represent different numbers. For example, the upper bead and the lower bead can be combined to represent the number 6. When calculation is needed, the combination of the upper bead and the lower bead can be used to represent different numbers, and calculation such as addition, subtraction, multiplication and division can be performed.
4. Usage of the upper bead and the lower bead: When using the abacus, the number is usually placed on the frame of the abacus first, and then the upper bead and the lower bead are moved with your fingers to calculate. In order to ensure the accuracy of calculation, it is necessary to pay attention to the figures represented by each file, and each file can only put one upper bead and one lower bead at most.
5. History of the Upper and Lower Beads: The abacus is an ancient calculation tool, and its origin can be traced back to ancient China. According to historical records, abacus first appeared in the Southern and Northern Dynasties in China, and then gradually spread to other parts of Asia and around the world. Now, abacus has become one of the important tools for mathematics education and cultural inheritance.
The history of abacus
1. In ancient times, people used various methods to calculate, such as fingers, stones and chips. With the development of commerce and handicraft industry, the requirements for calculation speed and accuracy are getting higher and higher, so more complex calculation tools appear.
2. China is the hometown of abacus, and the earliest abacus in China appeared in the Southern and Northern Dynasties. At that time, the form and structure of abacus were relatively simple, with wooden abacus, few files and no beads. With the passage of time, the abacus has gradually developed into a decimal calculation tool, forming the concept of "abacus calculation".
3. In Ming Dynasty, abacus was further developed and perfected. People began to make abacus with ivory, copper, iron and other materials, and there appeared "eighteen files" or even "twenty-one files" big abacus. This big abacus not only represents a technological progress, but also embodies the popularization and application of mathematics and computing knowledge.
4. Besides China, other countries and regions have calculation tools similar to abacus. For example, the "sand table" in Egypt and the "counting board" in India. However, China's abacus is the most widely used in history and has become an important part of China culture.