Sale! Sale! Sale!

Consumer math often requires shoppers to analyze and compare the same products at different stores. In addition to price variations, retailers offer incentives or discounts. This lesson requires students to be informed consumers who calculate three purchasing options and conclude which is the best deal. The activity enables students to apply mathematics to a real-life situation.

A lesson plan for grades 6–7 Mathematics

By Leslie Hawes

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Related topics

• Learn more about decimals, fractions, mathematics, percents, and sales tax.

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Learning outcomes

Students will:

• analyze and evaluate sale ads to determine the value of the discount communicated.
• relate decimals, fractions, and percents by converting all values to decimals.
• calculate final costs of products.
• organize and label the results in a chart format.

Teacher planning

Time required for lesson

90 Minutes

Materials/resources

• calculators (optional)
• pencil/paper
• ruler
• copies of sale ads
• white paper for chart

Pre-activities

The teacher needs to have copies of ads ready to pass out. Also have a format ready for guided practice so that the students will know how to label and arrange their problem solving solutions.

Students should already have basic knowledge of fraction, decimal, and percent relationships, in addition to the algorithms of multiplying fractions and decimals. This lesson provides problematic tasks that incorporate all of the previously mentioned concepts.

Activities

1. The teacher models a scenario, buying pizza. As guided practice, the class works on the problem together to find the new sale price offered by each restaurant, and then applies the NC 6% sales tax for total cost.
   • Pizza Hut: $13.99 at 20% off + tax = $11.86
   • Dominos: $14.00 at 1/4 off + tax = $11.13
   • Franks: Pay only 3/5 of $16.50 + tax = $10.49

   Teacher must organize the information on the board or overhead in a chart format communicating the name of the business, sale ad information, detailed calculation, new sale price, tax, and total cost. (Label these answers through the process.) Circle the restaurant that offers the best deal. Be sure to point out all details of the process while instructing students to show ALL work.

2. Students are given the sale ads of retailers and their competitors for independent practice. Students are directed to use the example on the board as a model for organization and layout of information. Each product to purchase has three retailers for which to compare and this could take a whole side of a piece of paper (8.5 X 11) divided into 3 sections using a ruler. (I suggest students take as much paper as possible so that they can spread out their problem solving steps.)
3. Students work individually or in pairs.

Assessment

Students will be assessed by the accuracy of their problem solving process, which should be clearly labeled on their charts. With each step of the problem labeled, the teacher and the student can pinpoint a specific problem, whether it is was the discount calculated, new sale price, sales tax, or total cost.

As teacher is monitoring independent practice, remind students that their answers should be realistic and not higher than the original price.

Supplemental information

These are the shopping situations that I have created. I usually print them all on the same sheet and students transfer their ads to a 3-column format. The chart format should follow the format used in guided practice. Answers for the final cost of product is given at the end of each ad description.

• VCR
• Sams: $188.00 1/5 off original price = $159.43
• Sears: $170.00 15% discount = 153.17
• K-Mart: $165.00 Pay only 9/10 on every dollar of purchase price = $157.41
• STEREO UNIT
• Sears: $180.00 On sale Now! 20% off = $152.64
• Walmart: $199.00 10% off plus a $20 Rebate = $168.65
• Circuit City: $175.00 3/20 Of the original price is FREE! = $157.68
• LEVI’S
• Belk: $44.00 one-third off = $31.25
• Dillards: $48.00 discount of 1/4 = $38.16
• Macys: $52.00 Pay 65% of original price = $35.83
• PEPSI 12-PACK
• Ingles: $5.00 Pay only 85% of original price = $4.50
• Bi-lo: $6.00 Pay 3/5 of Original Price = $3.82
• Harris Teeter: $5.50 Receive a discount of 1/3 = $3.91
• ADIDAS SHOES
• Legend’s: $88.00 Discount of 1/5 = $74.62
• Footlocker: $82.00 Pay .10 of regular price = $78.23
• Champs: $94.95 25% off! = $75.49

Comments

An option for this lesson would be to set the classroom up in stations, where there is one product being compared at each station and the students rotate. New shopping situations can be created and presented on posters with pictures for a more “shopping” atmosphere. Small groups or partners would work well in this type of arrangement.

If you choose not to allow the students to use calculators, I would suggest reducing the number of problems, as to avoid student frustration.