## What Does Percent Have to Do with It?

### Sharla ShultsBay District Schools

#### Description

Confused about percentages at the mall? Students go shopping for a true real-life experience involving percent. Exposure to percent relative to sales tax and discount prices is experienced in this lesson.

#### Objectives

The student refines vocabulary for interpersonal, academic, and workplace situations, including figurative, idiomatic, and technical meanings.

The student locates, gathers, analyzes, and evaluates written information for a variety of purposes, including research projects, real-world tasks, and self-improvement.

Understands the relative size of integers, rational numbers, irrational numbers, real numbers and complex numbers.

Understands concrete and symbolic representations of real and complex numbers in real-world situations.

#### Materials

-Sample newspaper advertisements for sales at a percentage or fraction of the total cost
-Business fliers advertising special sales at a percentage or fraction of the total cost
-Copies of documents found in the associated file prepared for class discussion and formative assessment (See Teacher Preparation for list.)
-Teacher computer with Data Display Panel
-Student Computers (optional)
-Student Calculators – basic FCAT – one per student

#### Preparations

1. Have folders ready for distribution at the beginning of class

2. Download and duplicate copies of the following documents found in the associated file:
a) Warm-Up Activity #3 – one per student
b) Warm-Up Activity #3 Answer Key – one copy for teacher use
d) Percent in the Real World Problem-Solving Activity Sheet – one per student
e) Percent in the Real World Problem-Solving Answer Key – one copy for teacher use

3. Set up overhead projector for class discussion and secure enough overhead pens for demonstration.

4. Download, print, and make Transparency for Discussion on Credit Card Charges and Transparency for Discussion of Effects of Changing Sales Tax Rates found in the associated file.

5. Secure a set of classroom calculators, FCAT style. Scientific calculators are not necessary.

6. Visit suggested Web sites to become familiar with information provided.

7. Prepare extra worksheets as needed for students having difficulty with basic arithmetic skills. These reflect areas of difficulty as demonstrated in problem solving with percents.

#### Procedures

Day 8 of the unit The Math Connection

Steps #1, #2, #15, and #16 are for teachers using the Unit Plan. For a stand-alone lesson of percent in the real world, please begin with Step #2 and end with Step #13.

NOTE UNIT PLAN: Letters should be arriving during this week. Since the letters will be coming in to the school, don’t forget to make a teacher’s copy to keep in a separate folder. This is a backup in the event students’ folders or materials are misplaced. Also, keep a checklist as the letters arrive. Distribute copies of the Rough Draft Comments Sheets to students to complete as they receive their letters. This document is found in the associated file of the lesson To Whom It May Concern to be duplicated as needed. Instruct students to write thank you notes to the contact persons for taking the time to answer the letters and make copies for the portfolio.

1. With student assistance, distribute student folders at the beginning of the class period.

2. Return The Decimal Dilemma Problem Solving practice sheets with feedback on weak areas for students to place in folders. Especially note to students any areas of weakness in arithmetic skills. Tell students to be mindful of any additional practice sheets attached to their returned papers. Remind students to place the problem-solving practice sheets in their folders and take home the attached sheets for extra practice.

3. Distribute the Warm-Up Activity #3 and tell students to work with partners in answering general questions about percent in the real world. Hold a class discussion covering the information gathered.

4. One of the most common places to encounter percent is at the mall. Discuss with students different ways of advertising sales. Use both percents and fractions in the discussion. Share samples of newspaper advertisements, sales fliers, or catalogs with students as examples. Demonstrate differences, such as 1/3 off and 30% off and discuss which would give the greater discount and why. Demonstrate equivalences, such as, 50% off and ˝ off, and discuss why they yield the same amount of discount.

5. Next discuss sales tax. Students know that taxes are applied, but many do not understand the process involved in the calculation of the amount of sales tax. As a suggestion, discuss various tax rates and the effect of a rise or fall of ˝ percent. Provide examples of items purchased applying a sales tax of 7% vs. items purchased applying a tax increase to 7˝% and a tax decrease to 6˝%. Compare the overall cost of all purchases at the varying tax rates using low prices and high prices so students can get a clear picture of the effect of change in rate. Emphasize with students that the less amount purchased will result in the least negligible change. Refer to the Transparency for Discussion of the Effect of Changes in Sales Tax Rates found in the associated file for examples.

6. A good question to explore during this time is, “Will this be cash or credit?” Discuss both disadvantages and advantages of either. Expose students to another important area of what percent has to do with real-world applications through the discussion of credit card charges, annual fees, and varying interest rates.

7. Explore Internet site The Calculator Web – Credit Card Calculator: http://www.calculatorweb.com/calculators/creditcardcalc.shtml. (See Weblinks below.) Two options are available to utilize this in the classroom. One option is for the teacher to use the computer and data display panel to set up a demonstration. The second option is for students to explore the Internet site hands-on with teacher guidance and assistance. With either option, follow steps #8 and #9 for presentation.

8. Use the Transparency for Discussion on Credit Card Charges found in the associated file to discuss the entries that are necessary for credit card charge calculations. The boxes for amounts and percentages are left blank for use with overhead pens to change entries for demonstration purposes.

9. Demonstrate or give students varying interest rates and monthly payment amounts to practice on the Internet site for a good clear picture of how the amount of interest charged fluctuates according to these factors. Be sure to practice using this site before introducing to students. Use dollar amounts ranging from \$40 to \$4000, interest rates from 11.5% to 24.5%, and minimum payment amounts ranging from \$10/month to \$200/month depending on the current account balance entered.

10. Tell students: Now, let’s go shopping. (Decide whether you prefer this to be an independent, partner, or group activity. If students are working in groups, create a way that they can be partnered or grouped effectively.) Distribute the Sales Advertisement Sample Page and Percent in the Real World Problem-Solving activity sheets to students, pair of students, or groups. (See Associated File.)

11. Instruct students to complete the questions and/or solve the problems as presented on the problem-solving sheet. Students need access to a computer to complete Problem #9 on the problem-solving activity sheet either as a group or independently. Suggested method of instruction: Answer Questions 1 - 5 as a whole group with lots of discussion. Have the students complete Questions 6 - 8 in small groups. Then, have students answer Question #9 individually at the computers.

12. Monitor students’ progress and lend assistance when needed. Allow students to ask questions and discuss openly any areas of concern that may arise.

13. While students are completing the problem-solving activities, collect students’ folders. The added documents of today’s lesson include the Decimal Dilemma Problem Solving, Warm-Up Activity #3 and the Sales Advertisement Sample Page.

14. Allow time to discuss with students the various occupations that go hand-in-hand with the problem solving. This reinforces the math connection between mathematics and the world of work. Look for student responses such as cashier, advertising agent, business manager, bankers, credit card companies, etc.

15. For homework, assign students the task of finding the answer to the following question: What is the name of the highest possible number? Tell students to explore as many resources as desired, i.e., books, encyclopedias, Internet, etc.

16. Collect students’ Percent in the Real World Problem-Solving activity sheets at the end of the class period to return the following day. Check students’ problem solving skills using the Sales Advertisement Problem Solving Answer Key found in the associated file. Identify any students struggling with the problem solving due to the inadequacy of understanding percent. Attach additional practice work sheets as needed to the percent problem solving activity sheets and return to students the next day to take home for extra practice.

*Note: If deemed necessary, adapt the checklist provided in the associated file of Rising and Falling Fractions to record the results for percent.

#### Assessments

This assessment aligns with the part of the standard only dealing with percent in real-world situations. Students understand concrete and symbolic representations of percent in real-world situations represented in a variety of equivalent forms and the relative size of integers as demonstrated on the Percent in the Real-World Problem-Solving practice sheet. (See Associated File.) Students analyze and evaluate the information from the text within the real-world math problems presented for solving. Students demonstrate understanding by correctly solving the problems. Students are formatively assessed using the answer key provided in the associated file. Vocabulary is embedded throughout the lesson plan allowing students to refine vocabulary for interpersonal, academic and workplace situations.

#### Extensions

This is Lesson 8 of 10 in the unit The Math Connection addressing [When Are We Ever Going to USE This MATH?]

The Beacon Unit Plan associated with this lesson can be viewed by clicking on the link located at the top of this page or by using the following URL: http://www.beaconlearningcenter.com/search/details.asp?item=2947. Once you select the unit’s link, scroll to the bottom of the unit plan page to find the section, “Associated Files.” This section contains links to the Unit Plan Overview, Diagnostic and Summative Assessments, and other associated files (if any).

The next set of Web links reference credit card charges.
The Credit Card Charges Calculator TM

The next set of Web links reference credit card charges.
The Calculator Web – Credit Card Calculator

Credit Card Calculator
Calculator Web

Provide Transaction Details and Calculate Charges
The Credit Card Charges Calculator TM

What You Need to Know About: Mathematics
Mathematics Tutorials

Interactive Math Lessons and More!
Understanding Percents

From Definition to Illustration
Math.com: Percents

Percent – From First Glance to Workout
Math.com

Two Categories: 1-Percent, 2-Chances and Probability
Percent and Probability

When Are We Ever Going to USE This Math?
The Math Connection