Absolute Value
The Meaning of Absolute Value of a Number: http://www.youtube.com/watch?v=L8fGfc7Wcco
Algebraic Absolute Value Equations and Inequalities: https://sites.google.com/site/harlandclub/Home/math/algebra/absvalue
Graphing Absolute Value Functions such as y = |x| or f(x)=|x|: https://sites.google.com/site/harlandclub/Home/math/algebra/absvalue/graphabsvalue