In this lesson, students continue to write equations of the form to represent proportional relationships. They begin to recognize situations where using the equation is a more efficient way of solving problems than other methods they have been using, such as using tables or equivalent ratios.

The activities introduce new contexts without providing tables. Students who still need tables should be given a chance to realize that fact and create tables for themselves. The activities are intended to motivate the usefulness of representing proportional relationships abstractly with equations (MP2). The repeated calculations called for in the activities serve as scaffolding for finding the equations (MP8).