Lesson Objective: Apply understanding of proportional relationships and use tape diagrams to model relationships and solve problems.

Students apply what they have learned about proportional relationships to decipher a cryptic recipe that describes the relationship between amounts of ingredients, but no actual measurements.

Students engage in Mathematical Practices 1 and 4 in this lesson. They must make sense of the problem (MP.1) because, once again, no prompts are given about how to begin. They must also persevere in solving the problem because of its nonlinear structure; they may reach a point at which they are using trial and error, and then must draw on new information (the size of the whole batch). Students model the relationships using tape diagrams (MP.4) in both the task and the exit ticket, ensuring that relationships are maintained regardless of the amounts being used.

**Key vocabulary:**

- proportional relationship