倒数、相反数是有理数一章中两个重要概念．学习时要注意以下几点：一、理解定义只有符号不同的两个数，把其中的一个叫做另一个的相反数，零的相反数是零；乘积是1的两个数叫做互为倒数，零没有倒数．二、掌握性质由倒数、相反数的定义可知，两个相反数的和为零，两个倒数的乘 The inverse and inverse are two important concepts in the rational number chapter. Learning to pay attention to the following points: First, understand the definition of only two different numbers of symbols, one of which is called the opposite of the other, zero is the opposite number is zero; the product is one of the two numbers are called each other is reciprocal, Zero does not count down. Second, to grasp the nature of the reciprocal, the inverse number of the definition, we can see that the sum of two opposite numbers is zero, multiply the two reciprocals