Chapter+5

5.1 and 5.2 http://www.khanacademy.org/math/arithmetic/basic-ratios-proportions/v/introduction-to-ratios--new-hd-version

5.3 http://www.khanacademy.org/math/arithmetic/basic-ratios-proportions/v/ratios-as-fractions-in-simplest-form

5.8 http://www.khanacademy.org/math/arithmetic/basic-ratios-proportions/v/finding-unit-rates