This standard is one of the most challenging standards in the 6th grade Common Core. This lesson breaks down the procedures in a step-by-step manner for determining the number of unit cubes that can fit into a right rectangular prism. There is a quick warm-up to review the concept of volume. Then there is a tutorial on what it "looks" like to pack a shape with unit cubes and how to find the answer mathematically. There are 5 practice problems for students to try to find the number of unit cubes in a right rectangular prism.