In this lesson, students apply the strategies for reasoning about situations involving equivalent ratios to solve an unfamiliar, Fermi-type problem. Students must take a problem that is not well-posed and simplify the problem so that it can be solved.

To understand the problem, students need to break down a larger question into more-manageable sub-questions, which requires sense making and perseverance (MP1). To solve the problem, they need to make assumptions and approximations, plan an approach, and reason with the mathematics they know. Engineers, computer scientists, physicists, and economists often make simplifying assumptions as they use mathematics to tackle complex problems. This process is central to mathematical modeling (MP4).

Later in the course, students will have more opportunities to explore and solve Fermi problems and engage in mathematical modeling.