VIDEO #1 Rates and Unit Rates
http://www.virtualnerd.com/middle-math/ratios-proportions-percent/ratios-rates/rate-and-unit-rates-definition
VIDEO #2 Converting Rates to Unit Rates
http://www.virtualnerd.com/middle-math/ratios-proportions-percent/ratios-rates/rate-to-unit-rate-conversion
VIDEO #4 Using Unit Rates to Compare
http://www.virtualnerd.com/middle-math/ratios-proportions-percent/ratios-rates/compare-unit-rates-example