In mathematics, the first level is the collective name of four counting units: 1, 10, 100, 1000.

10,000 is a general term for 10,000, 100,000, 1 million and 10 million.

Billion class is the collective name of four counting units: billion, billion, billion and hundred billion.

Extended data:

Grading principles of several grades:

1, four-digit classification method

That is, a four-digit grading method. The habit of reading in our country is like this. Such as: ten thousand (four zeros after counting) and trillion (there are two kinds of sayings, one is one million, that is, six zeros after counting; The second is trillion, that is, 12 zeros after the number) and 1 billion (8 zeros after the number), which is the Sino-French count). These levels are called level, level and level respectively.

2. Three-digit classification

That is, the three-digit grading method. This western classification, this classification is also an internationally accepted classification. That is, take the decimal point as the center and add a comma to every three numbers in the integer part from right to left. Such as: thousands (three zeros after counting), millions (one million, six zeros after counting), and billions (one billion, nine zeros after counting).

Baidu encyclopedia-several levels