From the point of view of mathematics and grammar:

1: If "ten" is used, it is represented by Chinese characters10;

2. If I use "10", it means that I default to the counting method of Arabic numerals, the mathematical meaning of the number "1", the mathematical meaning of "0", the piano axiom and the ZFC axiom system ... although I have never heard of these things.

10: "Ten" is a word and "10" is a math. Why can we be universal in our daily life? (actually, it is not common. When writing a paper, you should use Arabic numerals to represent numbers. Only idioms, common words and special nouns can use Chinese characters. It is because we acquiesce in the counting method of Arabic numerals, the mathematical meaning of the number "1", the mathematical meaning of "0", the piano axiom and the ZFC axiom system ... although I have never heard of these things. We think "ten" and "10" are the same thing. Is it actually the same thing? Not exactly.

Others have said that the Arabic numeral "20" is more obvious. In terms of words, English "twenty" and Chinese "twenty" are both one word. The reader said, no, the Chinese character "20" is "20", which is completely corresponding. In fact, this just shows the difference between words and mathematics: mathematical expression is more rigorous than written expression.

80: "Ten" is, in the final analysis, a language or character symbol, which represents a number in Chinese and Japanese. This number is numerically equivalent to the decimal "10" expressed in Arabic numerals. As for why the Chinese character "ten" occupies fewer characters than the Chinese character "one" and the Arabic numeral "1 0" relative to the Arabic numeral "1". That should start with the origin of Chinese characters. Why not explain the French word "80" first?