相反数和绝对值是中学数学中及其重要的概念,这节内容既是七年级教材的一个重点,又是难点,与绝对值有关的题目在各类考试中经常出现,题型灵活多变,技巧性强,它的应用十分广泛,因此我们对它应该引起足够重视.由相反数的概念不难看出:(1)从数轴上看,除了零以外互为相反数的两个数,它们分别在原点的两旁且离原点的距离相等. Opposite number and absolute value of mathematics in secondary school and its important concept, the content of this section is not only a focus of the seventh grade textbook, but also difficult, and the absolute value of the topics often appear in various exams, the question is flexible, Because of its skillfulness and its wide application, we should pay enough attention to it.It is easy to see from the concept of the opposite number: (1) From the axis of numbers, On both sides of the origin and at the same distance from the origin.