任何一个有理数可以用数轴上的点表示。一个数a的绝对值就是数轴上表示数a的点与原点的距离。因此 ,在数轴上表示一个数的点到原点的距离 ,只需要求出这个数的绝对值即可。例 1　在数轴上表示一个数的点到原点的距离是 3,求这个数。解 :设这个数是x ,则 |x| =3∵ |± 3| =3,∴x Any rational number can be represented by points on the axis. The absolute value of a number a is the distance between the point on the number axis that represents the number a and the origin. Therefore, to represent the distance from the point of a number to the origin on the axis, you only need to ask for the absolute value of this number. Example 1 On the axis, the distance from the point to the origin of a number is 3, find this number. Solution: Let this number be x, then |x| =3∵ |± 3| =3,∴x