In this lesson, students learn to use tape diagrams to distinguish division situations where the quotient represents the size of each group (for example, "Ms. Alves puts 21 papers in 7 piles. How many papers are in each pile?"), and situations where the quotient represents the number of groups (for example, "There are 8 crackers, but this time each student gets 2. How many students get crackers?"). They also relate division sentences to multiplication to emphasize the concept of division as an unknown factor problem.