绝对值是指一个数在数轴上所对应点到原点的距离，用“| |”来表示。|b-a|或|a-b|表示数轴上表示a的点和表示b的点的距离。(Absolute value refers to a number corresponding to the distance to the origin in the axis, with "| |" said. The |b-a| or |a-b| axis A and B said that the distance from the point.)