Why is the absolute value of 0 always 0?

Absolute value changes the sign of a number to positive, so negative one becomes positive one, and positive one stays positive one. Zero has no sign, and is therefore equal to its absolute value. If you use a graphing calculator, or a graphing program (online or installed software), and graph y equal to theabsolute value of x, you will see two lines, y=x from 0 to infinity and y=(-x) from 0 to negative infinity. When x=0, the two lines are the same because the negative of 0 is still 0.