Lesson 17

Negative Rates

Lesson Narrative

The purpose of this lesson is to introduce students to negative rates of change, which will become important when they start learning about linear functions in later lessons. Students apply their understanding of operating with signed numbers to solve problems in context. The first problem involves a fish tank that is being filled and drained. The second problem deals with historic voyages in a bathyscaphe (deep-sea submarine) and a high-altitude hot air balloon. When students reason quantitatively about what it means for a rate to be negative, they engage in MP2.

The activities in this lesson involve more reading than most lessons. Be prepared to support students with unfamiliar words.

Teacher Notes for IM 6–8 Accelerated
This lesson is optional. It provides opportunities for students to apply multiplying and dividing rational numbers to solve problems. The third activity incorporates all four operations with rational numbers.

Learning Goals

Teacher Facing

  • Apply operations with signed numbers to solve problems involving constant rates, and explain (orally) the solution method.
  • Explain (orally and in writing) how signed numbers can be used to represent situations involving constant rates.
  • Write an equation of the form $y=\text-kx$ to represent a situation that involves descending at a constant rate.

Student Facing

Let's apply what we know about signed numbers.

Learning Targets

Student Facing

  • I can solve problems that involve multiplying and dividing rational numbers.
  • I can solve problems that involve negative rates.

CCSS Standards

Print Formatted Materials

Teachers with a valid work email address can click here to register or sign in for free access to Cool Down, Teacher Guide, and PowerPoint materials.

Student Task Statements pdf docx
Cumulative Practice Problem Set pdf docx
Cool Down Log In
Teacher Guide Log In
Teacher Presentation Materials pdf docx

Additional Resources

Google Slides Log In
PowerPoint Slides Log In