Multiple Percents - What happens when you have a discount and tax?

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Objective

Students will be able to solve problems involving multiple percentages.

Big Idea

No no no!!! You CANNOT combine percents! In this lesson students will learn to avoid making one of the most popular percent mistakes.

Launch

10 minutes

OpenerAs students enter the room, they will immediately pick up and begin working on the opener – Instructional Strategy - Process for openers.  This method of working and going over the opener lends itself to allow students to construct viable arguments and critique the reasoning of others, which is mathematical practice 3

Learning Target:  After completion of the opener, I will address the day’s learning targets to the students.  For today’s lesson, the intended target is, “I can solve multi-step percent problems.” Students will jot the learning target down in their agendas (our version of a student planner, there is a place to write the learning target for every day). 

Thoughts from Me! Students will need to pay careful attention to precision when moving the decimal point and completing the calculations (mathematical practice 6).  Percents lend themselves to real world application problems, requiring students to model and reason given models (mathematical practices 2 and 4). Students will be permitted to use tools as needed - calculators and bar models (mathematical practice 5). 

Explore

45 minutes

Discussion Question:  To start the lesson off, I am going to pose the following question to my students:  "A sweater is priced $60.  It is on sale for 50% off.  Later it goes on sale for an additional 50% off.  What is the price of the sweater?"  The point of this discussion question is to introduce kids to the fact that they cannot combine percents, they must calculate them seperately.  Many students I am sure will think that the sweater is free - but this opens up good discussion and gets kids interested in the lesson.

Multiple Percents NotesMultiple Percents Explore Video

Summary

5 minutes

Exit Problem: To summarize this lesson, I will have students complete an exit problem on the back of their opener.  We have been working on the same concept for 8 lessons, so at this point I am looking for some individual feedback on understanding.  This exit problem will give me insight into who understands tax, discount, and a combination of both concepts.