Arabic numerals

Arabic numerals were invented by ancient Indians and later spread to Arabia and Europe. Europeans mistakenly thought it was invented by Arabs, so they called it "Arabic numerals". Because it has been circulated for many years, people call it Yi, so people still mistakenly believe that these numerical symbols invented by ancient Indians are called Arabic numerals.

multiplication table

Jiujiuge is the multiplication formula we use now. As early as the Spring and Autumn Period and the Warring States Period BC, Jiujiu songs have been widely used by people. In many works at that time, there were records about Jiujiu songs. The original 99 songs started from "99.8 1" to "22.24", with 36 sentences. Because it started with "998 1", it was named 99 Song.

The expansion of Jiujiu Song to "One for One" was between the 5th century and10th century. It was in the 13 and 14 centuries that the order of Jiujiu songs became the same as it is now, from "one for one" to "9981". At present, there are two kinds of multiplication formulas used in China. One is a 45-sentence formula, usually called "Xiao Jiujiu"; There is also a sentence 8 1, which is usually called "Big Uncle Nine".

Third, Mobius ring

Mobius ring is a topological structure with only one face and one boundary. You can twist a piece of paper into 180 degrees, and then stick the two ends together to form a Mobius ring.

Cutting Mobius ring along the midline can get a larger ring for the first time. The second time and after, you will get two nested rings every time. The middle will never break, which is also the magic of Mobius ring.

1. Mathematics is a subject that studies concepts such as quantity, structure, change and spatial model. By using abstract and logical reasoning, the shape and motion of objects are counted, calculated, measured and observed. Mathematicians have extended these concepts in order to express new conjectures with formulas and establish strictly deduced truths from properly selected axioms and definitions.

2. Mathematical attribute is the measurable attribute of anything, that is, mathematical attribute is the most basic attribute of things. The existence of measurable attributes has nothing to do with parameters, and the result depends on the selection of parameters. For example, time, whether measured in years, months, days or hours, minutes and seconds; Space, whether measured in meters, microns, inches or light years, always has their measurable properties, but the accuracy of the results is related to these reference coefficients.

3. Mathematics is a science that studies the quantitative relations and spatial forms in the real world. Simply put, it is the science of studying numbers and shapes. Due to the needs of life and labor, even the most primitive people know simple counting, and it has developed from counting with fingers or objects to counting with numbers.