Inverse number is a mathematical term, which means that two numbers with equal absolute values and opposite signs are opposite to each other.

Reciprocal attribute:

1. Antique features: If A and B are inverse numbers, A+B = 0; Otherwise, if a+b=0, a and b are inverse numbers.

The reciprocal of zero is 0.

3. Antiquities appear in pairs and cannot appear alone.

4. Distinguish between "opposite numbers" and "quantities with opposite meanings". "Inverse number" is not only the opposite sign of a number, but also the numbers after the sign must be the same, such as +5 and -5, while "quantities with opposite meanings" only need the opposite sign, such as +3 and -7.

5. To ask the reciprocal of a number, just add a negative sign in front of the number. If the original number is signed (whether positive or negative), it should be put in parentheses first.

6. the inverse of the number a is -a, and the inverse of -a is a, where a is not necessarily a positive number, so -a is not necessarily a negative number.

7. When simplifying multiple symbols, it should be noted that when a positive number is preceded by an even "-",it can be simplified to the number itself.

For example: -[-(7)]=7 (According to the multiplication rule of rational numbers, the same sign is positive and the different sign is negative. )

8. When simplifying multiple symbols, it should be noted that when a positive number is preceded by an odd number of "-"signs, it can be simplified to the opposite number of this number.

Method formula:

"Odd negative even positive", where "parity" is the number of ""before positive number, and "negative positive" refers to the symbol of the final result of simplification.