This lesson uses the structure of the first lesson in this section, in which students estimated how much milk different groups of students drink in a day and how many days it would take the students to drink specified amounts of milk. In this lesson, students make similar estimates and calculations, but now they are estimating the volume of recyclable garbage produced at their school. Continuing the context of the previous lesson as well as the large numbers, students start to conceptualize how much recyclable garbage the United States produces and ships overseas. They first encountered this context at the end of the first unit and now can use the whole-number multiplication and division strategies they learned in this unit to study the situation in greater depth. Because there are a lot of estimates involved, students also see a quotient of numbers much greater than they have seen to this point. They find the value of this quotient, using known facts and reasoning about place value.

Throughout the lesson, students make estimates and simplifying assumptions in order to answer complex mathematical questions (MP4).