Equations and Inequalities

Lesson 12

Math

Unit 4

7th Grade

Lesson 12 of 12

Objective


Model with inequalities.

Common Core Standards


Core Standards

  • 7.EE.B.3 — Solve multi-step real-life and mathematical problems posed with positive and negative rational numbers in any form (whole numbers, fractions, and decimals), using tools strategically. Apply properties of operations to calculate with numbers in any form; convert between forms as appropriate; and assess the reasonableness of answers using mental computation and estimation strategies. For example: If a woman making $25 an hour gets a 10% raise, she will make an additional 1/10 of her salary an hour, or $2.50, for a new salary of $27.50. If you want to place a towel bar 9 3/4 inches long in the center of a door that is 27 1/2 inches wide, you will need to place the bar about 9 inches from each edge; this estimate can be used as a check on the exact computation.
  • 7.EE.B.4.B — Solve word problems leading to inequalities of the form px + q > r or px + q < r, where p, q, and r are specific rational numbers. Graph the solution set of the inequality and interpret it in the context of the problem. For example: As a salesperson, you are paid $50 per week plus $3 per sale. This week you want your pay to be at least $100. Write an inequality for the number of sales you need to make, and describe the solutions.

Foundational Standards

  • 6.EE.B.5
  • 6.EE.B.8

Criteria for Success


  1. Analyze real-world situations and identify important information needed to solve a problem.
  2. Create inequalities to model real-world applications and use them to test out solutions (MP.4).

Tips for Teachers


This lesson includes a three-act task for the Anchor Problems , aligned to the objective. The Problem Set Guidance includes and recommends spiraled review of skills and concepts from the unit. 

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Anchor Problems


Problem 1

Act 1: Watch the video of Sweet Snacks Act 1.

a.   What do you notice? 

b.   What do you wonder?

Guiding Questions

Create a free account or sign in to access the Guiding Questions for this Anchor Problem.

References

Andrew Stadel's 3-Act Math Tasks Sweet Snacks

Sweet Snacks from Andrew Stadel's 3-Act Math Tasks is made available by Andrew Stadel. Accessed Nov. 9, 2017, 5:52 p.m..

Modified by Fishtank Learning, Inc.

Problem 2

Act 2: Watch the video of Sweet Snacks Act 2

a.   Does the man have enough money to pay for what he put in his cart? 

b.   What are some combinations of Teddy Grahams and Circus Animal Cookies that he can afford?

Guiding Questions

Create a free account or sign in to access the Guiding Questions for this Anchor Problem.

References

Andrew Stadel's 3-Act Math Tasks Sweet Snacks

Sweet Snacks from Andrew Stadel's 3-Act Math Tasks is made available by Andrew Stadel. Accessed Nov. 9, 2017, 5:52 p.m..

Modified by Fishtank Learning, Inc.

Problem 3

Act 3: Watch video of the solution to Sweet Snacks Act 3.

Was your answer reasonable? Why or why not?

Guiding Questions

Create a free account or sign in to access the Guiding Questions for this Anchor Problem.

References

Andrew Stadel's 3-Act Math Tasks Sweet Snacks

Sweet Snacks from Andrew Stadel's 3-Act Math Tasks is made available by Andrew Stadel. Accessed Nov. 9, 2017, 5:52 p.m..

Modified by Fishtank Learning, Inc.

Problem Set

Fishtank Plus Content

Give your students more opportunities to practice the skills in this lesson with a downloadable problem set aligned to the daily objective.

Target Task


Isaiah is filling 12 small plastic bags with candy for a party. He puts 2.5 pounds of candy into each bag, but then he reads on the package that there is a recommended weight limit so the bags do not break. Isaiah then takes out the same amount of weight from each bag.

a.   Which inequality best represents the situation? 

  1. a.   $$12x-2.5≤21$$

  2. b.   $$12(2.5-x)≤21$$

  3. c.   $$12(x-2.5)≤21$$

  4. d.   $$21-12x≤2.5$$

b.   Explain how the inequality you chose matches the situation. In your explanation, describe what the number 21 represents and what the variable represents. 

Student Response

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Additional Practice


The following resources include problems and activities aligned to the objective of the lesson that can be used for additional practice or to create your own problem set.

  • Include other review problems from earlier in unit on equations and inequalities.
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Lesson 11

Lesson Map

A7CB09C2-D12F-4F55-80DB-37298FF0A765

Topic A: Solving and Modeling with Equations

Topic B: Solving and Modeling with Inequalities

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