When it comes to the SAT math section, an absolute value is represented by two bars on both sides of either a number, variable or expression. Examples would be  |-4|, |x + 3|, and |-(x4 - 1)|. The absolute value is simply the distance from the number zero. Once a number leaves the bars so it can be worked with, it becomes positive.  Example  If you are given a negative value for the variable, it may be a trick question. Absolute value expressions do not become positive numbers until they are removed from the bars. Problems that ask for an easy substitution of a number into an absolute value expression are solved by getting rid of any negative answers.  This allows some answer choices to be eliminated.