Curriculum  /  Math  /  7th Grade  /  Unit 5: Percent and Scaling  /  Lesson 9

Percent and Scaling

Lesson 9

Math

Unit 5

7th Grade

Lesson 9 of 19

Objective

Solve percent applications involving discount, tax, and tip.

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.RP.A.3 — Use proportional relationships to solve multistep ratio and percent problems. Examples: simple interest, tax, markups and markdowns, gratuities and commissions, fees, percent increase and decrease, percent error.

Foundational Standards

  • 6.RP.A.3.C

Criteria for Success

  1. Solve percent applications involving more than one percent; for example, finding a restaurant bill including tax and a tip.
  2. Understand that multiple discounts are not additive but are taken sequentially where the order does not matter. 

Tips for Teachers

  • In Lessons 9–11, students apply the strategies and skills they learned so far in this unit to solve real-world percent applications (MP.4). In this lesson, students look at examples involving tax, tips, and price markups and markdowns. Ensure students have an adequate working knowledge of these concepts so they can access the problems appropriately.
  • In regards to pacing, this lesson may extend over two days if needed.
Fishtank Plus

Unlock features to optimize your prep time, plan engaging lessons, and monitor student progress.

Anchor Problems

25-30 minutes

Problem 1

For Simon’s birthday, he and his family go out to eat at a restaurant. 

a.   The amount of tax is $3.40, which is 5% of the food bill. How much was the food bill not including the tax?

b.   If Simon wants to leave a 20% tip on the amount of the food bill before tax, how much should he leave for a tip?

c.   What is Simon’s total bill including tax and tip? What percent of the food bill is this? 

Guiding Questions

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

Student Response

Upgrade to Fishtank Plus to view Sample Response.

Problem 2

Emily has a coupon for 20 percent off of her purchase at the store. She finds a backpack that she likes on the discount rack. Its original price is $60, but everything on the rack comes with a 30 percent discount. 

Emily says, “Thirty percent and twenty percent make fifty percent, so it will cost $30.”

Is Emily correct? Explain your reasoning. In your explanation, if you disagree with Emily, find the price she will pay for the backpack.

Guiding Questions

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

Student Response

Upgrade to Fishtank Plus to view Sample Response.

References

Illustrative Mathematics Double Discounts

Double Discounts, accessed on Dec. 18, 2017, 9:29 p.m., is licensed by Illustrative Mathematics under either the CC BY 4.0 or CC BY-NC-SA 4.0. For further information, contact Illustrative Mathematics.

Problem 3

In order to make money, a store marks up its prices by 25% from the warehouse prices. Let $$p$$ represent the price at which the store gets its merchandise from the warehouse, and let $$s$$ represent the price the store sells the merchandise for after the markup.

a.   Write an equation to determine the selling price, $$s$$, based on the warehouse purchase price, $$p$$.

b.   Create a table showing possible pairs of solutions to the equation.

Warehouse price ($$p$$) Selling price ($$s$$)
   
   
   
   

c.   Create and label a graph for your table.

d.   Interpret the points $$(0, 0)$$ and $$(1, r) $$ from the graph in context of the situation. 

Guiding Questions

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

Student Response

Upgrade to Fishtank Plus to view Sample Response.

References

EngageNY Mathematics Grade 7 Mathematics > Module 4 > Topic B > Lesson 7 — Exercise 4

Grade 7 Mathematics > Module 4 > Topic B > Lesson 7 of the New York State Common Core Mathematics Curriculum from EngageNY and Great Minds. © 2015 Great Minds. Licensed by EngageNY of the New York State Education Department under the CC BY-NC-SA 3.0 US license. Accessed Dec. 2, 2016, 5:15 p.m..

Modified by Fishtank Learning, Inc.

Problem Set

15-20 minutes

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

Target Task

5-10 minutes

Lauren and her sister are buying their mom a watch for her birthday. The original price of the watch is $50, but the store is having a 25% off sale on watches. The sales tax in Lauren’s state is 6%.

a.   How much will Lauren and her sister pay for the watch including tax?

b.   What percent of the original price do Lauren and her sister pay for the watch, after paying tax?

Student Response

Upgrade to Fishtank Plus to view Sample Response.

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.

  • Challenge: Asher paid $100.80 at a restaurant for his family's dinner. His bill included 5% for tax, and he added 20% of the total, including the tax, for the tip. What was the amount of the bill before tax and tip?

Next

Solve percent applications involving simple interest, commissions, and other fees.

Lesson 10
icon/arrow/right/large

Lesson Map

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

Topic A: Percent, Part, and Whole

Topic B: Percent Increase and Decrease

Topic C: Percent Applications

Topic D: Scale Drawings

Request a Demo

See all of the features of Fishtank in action and begin the conversation about adoption.

Learn more about Fishtank Learning School Adoption.

Contact Information

School Information

What courses are you interested in?

ELA

Math

Are you interested in onboarding professional learning for your teachers and instructional leaders?

Yes

No

Any other information you would like to provide about your school?

We Handle Materials So You Can Focus on Students

We Handle Materials So You Can Focus on Students

We've got you covered with rigorous, relevant, and adaptable math lesson plans for free