These links may be useful (click and go) during the PreAlgebra course:
Khan Academy has a huge library of videos across a multitude of topics:
http://www.khanacademy.org/
Review for adding and subtracting positive and negative numbers:
http://www.mathsisfun.com/positive-negative-integers.html
Textbook website:
Helpful student-created math videos:
A quick math dictionary with useful examples:
A great (!) graphing website:
https://www.desmos.com/calculator
This site is useful for creating bar graphs, line graphs, pie graphs, etc.
http://nces.ed.gov/nceskids/createagraph/default.aspx
A useful site...