Reciprocal is a mathematical term, and pinyin is dào shù. Mathematically, it means that the product of a number x multiplied by it is 1, and it is recorded as1/X. The process is "multiplication inverse", and all numbers except 0 have reciprocal. The numerator and denominator are inverted, the number whose product is 1 is reciprocal, and 0 has no reciprocal.

There are concepts such as group, field and ring in modern algebra, in which abstract multiplication operation and unit element are defined. Similarly, if there is a multiplication inverse, its multiplication can also be regarded as reciprocal.

Characteristics of reciprocal: A positive real number (except 1) plus its reciprocal must be greater than 2. A negative real number (except-1) plus its reciprocal must be less than -2.

The importance of learn mathematics:

1. Mathematics is closely related to our life. To say that the real effect of learning mathematics is not reflected in exam-oriented education, but in my own thinking about the future.

2. The importance of mathematics is self-evident. Mathematics is the foundation of all sciences and an important channel to cultivate logical thinking. It can be said that every major progress of our mankind is strongly supported by mathematics.

3. The application of mathematical knowledge in life is everywhere. From the calculation of daily living costs, to astronomy, geography, quality control, agricultural economy, aerospace, there are shadows of using mathematics.