Tuesday, February 3, 2009

PREP FOR GMAT: Absolute Value and Opposites

The absolute value of a number n is denoted by |n|.
It is defined as the distance between 0 (zero) and n (the number) on the number line.
Note: absolute value of any nonzero number is always positive.
For example, |10| = 10 and |-10| = 10.
Both 10and -10 have the same absolute value of 10, because 10 is 10 units from 0 (to the right) on the number line and -10 is 10 units from 0 (to the left).
Note: |-n| = |n| for any nonzero number n, and |0| = 0.

Two unequal numbers with the same absolute value are called opposites.
Both 10and -10 have the same absolute value of 10, but 10 is not equal to -10 ,hence they are opposites.
Note that the only number that is equal to its opposite is 0 (zero).