This document defines ratio, rate, and unit rate. It provides examples of how to calculate unit rate by dividing one number by another to get a comparison like miles per hour or dollars per item. It also gives examples of how to use a unit rate to find a total cost or amount by multiplying the unit rate by a quantity like hours or number of items. Finally, it shows how to calculate unit rates for two options and determine which is the better buy based on comparing the unit rates.