one

1, positive number: the number greater than 0 learned in primary school is called positive number.

1、? Negative number: A number preceded by a negative sign "-"is called a negative number.

2、? How to judge positive and negative numbers:

⑴ Specific figures: See if there is a negative sign "-",if there is a "-",it will be negative, otherwise it will be positive.

⑵ Numbers with letters: If -a depends on the symbol of A itself, if A is negative, then -a is positive, if A is positive, then -a is negative, if A is 0, then -a is 0.

3、? Meaning of 0: ①0 indicates the starting point. ②0 means no. ③0 means temperature. ④0 indicates the number of digits. ⑤0 indicates accuracy. ⑥0 indicates the boundary between positive and negative numbers. ⑦0 means the average altitude.

4、? A quantity with opposite meaning;

5、? The role of positive numbers and negative numbers: In the same problem, the quantities represented by positive numbers and negative numbers have opposite meanings.

Two?

1, rational number: integers and fractions are collectively called rational numbers.

Positive integers, 0, negative integers, positive fractions and negative fractions can all be written in the form of fractions, and such numbers are called rational numbers.

2, rational number classification:

3. Integers include: positive integer, 0 and negative integer.

4. Scores include: positive scores and negative scores.

5. Non-negative numbers: positive numbers and 0 are collectively called non-negative numbers.

6. Non-positive number: negative numbers and 0 are collectively referred to as non-positive numbers.