Lesson 5.1.2 – Teacher Notes Standard: 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. Chapter 7 – Focus on percentages. Lesson Focus: The focus is to provide students with repetitive practice of word problems involving ratios and percents. (5-14 and 5-16) I can recognize that a percent is a proportional relationship out of 100. Calculator: Yes Literacy/Teaching Strategy: Red-Light-Green-Light (Entire Lesson); Walk and Talk (closure)

How are sales advertised in different stores How are sales advertised in different stores?  In a clothing store, items are often marked with signs saying, “20% off” or “40% discount.”  In a grocery store, sale items are usually listed by price.  For example, pasta is marked, “Sale price 50¢,” or boxes of cereal are marked “$2.33 each.”  In the clothing store, you are able to see how much the discount is, but the price you will pay is often not stated.  On the other hand, sometimes in the grocery story it is not possible to tell the size of the discount.  It might only be a small fraction of the original price. The actual dollar amount of the discount and the percentage comparing it to the whole are important pieces of information that help you decide if you are getting a good deal.  Today you will create complete information about a sale situation from the information given in a problem. By the end of this lesson, you will be expected to answer these target questions: How can I find a percentage of a whole? How can I find a percent if I have two parts that make a whole? How can I find the whole amount if you know the parts?

5-14. Marisa is always looking for a great deal while shopping 5-14. Marisa is always looking for a great deal while shopping.  She found a sale rack where all of the jeans are marked 40% off.  Her favorite jeans regularly cost $65. a. To figure out if she has enough money to buy a pair of jeans, Marisa decides to estimate.  She thinks that the jeans will cost approximately $30.  Is her estimate reasonable?  Explain your thinking.   b. To find the exact answer, Marisa created the diagram below.  How could she add marks to partition the line evenly?  Partition the line and calculate the missing values.  c. How much money will Marisa save?  What is the price she will have to pay?  d. Marisa wants to check her answer from part (c).  How could she use ratios with the amount she saved and the original price to verify that she received a 40% discount? 

5-15. At the same sale, Kirstin sees a shirt on sale for just $37. 50 5-15. At the same sale, Kirstin sees a shirt on sale for just $37.50.  It originally cost $50. Estimate the percentage of the discount on the shirt.  a. Draw a diagram to represent this situation.  Label all parts.  b. What percent is the discount on Kirstin’s shirt? 

5-16. So far in this section, you have used a linear model to represent percent problems in various contexts. Obtain a Lesson 5.1.2 Resource Page and use the linear models to find parts and wholes when different types of information are provided on the diagrams.   a. For each diagram, write at least three statements describing how parts and percentages are related.  Some statements are started for you. 

You purchase a $750 television. You have to pay 7% sales tax. What will be your total cost?   2. Kim’s family spends $42.50 on dinner. They leave an 18% tip. How much is their total bill?  3. You purchase $220 airline ticket, but it is a last-minute purchase and you received 20% off the cost of the ticket. What was the discount and the sale price of the flight?   

4. You and three friends’ dinner cost $52. 40 4. You and three friends’ dinner cost $52.40. You want to leave your waiter a 20% tip. If you all split the cost, how much will each of you pay for your meal and the tip?    5. You are getting 25% off a great vacation which the regularly cost $ 436.00. How much will you pay for the vacation?