##
* *Reflection: Developing a Conceptual Understanding
Percent Change - By What Percent Did the Value Change? - Section 2: Explore

In the past I have always taught this concept using the ratio: difference/original. However, in an effort to keep things simple and not change the rules on kids - I approached percent change by using the percent equation - the same equation we have been using. I did not want students to have to remember an additional equation when the one they are already working with works :) Thus, to bring in the concept of change - once we worked backward to get the answer, students had to determine how much the percent changed from 100%. I kept reminding them that 100% is status quo - so how did we change the value, did we go up or down from 100%, and by how much?

Students seemed to grasp this method of teaching it better than they have in the past. I guess I will see over the next few days as students work with a mixed set of problems. See attached smartboard notes for how the class went!

*Developing a Conceptual Understanding: Explore Reflection*

# Percent Change - By What Percent Did the Value Change?

Lesson 16 of 21

## Objective: Students will be able to calculate percent of change.

## Big Idea: By what percent did the value change? Can you relate percent change to what we already know how to do? This lesson provides multiple methods of solving.

*60 minutes*

#### Launch

*10 min*

**Opener: **As 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 calculate percent change.” 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! **This concept lends itself to the use of **mathematical practices 2 and 4**, as most problems can be modeled using real world examples, and given those examples students have to reason both quantitatively and abstractly. Additionally, students are working with a decimal point - which can change the value of a number drastically if placed incorrectly, so it is important that students pay close attention to precision when working (**mathematical practice 6**).

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#### Summary + Homework

*5 min*

**Instructional Strategy - Table Discussion: **To summarize this lesson, I am going to ask that students have a table discussion considering the problem “A shirt costs $20, and after tax it costs $21. What is the percent of tax? Could this problem be solved using the percent change method? The reason I am having students talk about this problem is to draw connections to previous lessons, as well as shed light on another method of solving the problem. Students have already learned percent change, just in a different context, and the way that we learned to do it in earlier lessons does apply and is a valid way of solving the problems in this lesson.

**Percent Change Homework:** As students are having their table discussion, I will pass out the night’s assignment. This assignment allows students the opportunity to practice percent of change problems. Students will be asked to look over the assignment and identify any glaring questions before they leave class – I want all students to experience success!

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##### Similar Lessons

Environment: Urban

Environment: Rural

###### The Defining Pi Project, Day 1

*Favorites(4)*

*Resources(31)*

Environment: Urban

- UNIT 1: Introduction to Mathematical Practices
- UNIT 2: Proportional Reasoning
- UNIT 3: Percents
- UNIT 4: Operations with Rational Numbers
- UNIT 5: Expressions
- UNIT 6: Equations
- UNIT 7: Geometric Figures
- UNIT 8: Geometric Measurement
- UNIT 9: Probability
- UNIT 10: Statistics
- UNIT 11: Culminating Unit: End of Grade Review

- LESSON 1: Percent Models - A Visual Approach to Percents
- LESSON 2: Markdown Percent Models - What Percent Are You Paying?
- LESSON 3: Markup Percent Models - Percents Over 100?
- LESSON 4: Percent Models Review - Practice, Practice!!
- LESSON 5: Percent Models Test
- LESSON 6: Finding Percents
- LESSON 7: Finding Percents Fluency - It's a Chain Reaction!
- LESSON 8: Multiple Percents - What happens when you have a discount and tax?
- LESSON 9: Markup and Markdown Review - Are you paying more or less?
- LESSON 10: Markup, Markdown, or Just a Percent? TEST
- LESSON 11: Working Backwards with Percents - What happens when a problem is not straightforward?
- LESSON 12: Working Backward with Percent: Practice Makes Perfect!
- LESSON 13: Performing with Percents - Can you bust some common misconceptions?
- LESSON 14: More Practice with Percents - Practice Makes Perfect!
- LESSON 15: Working Backward and Forward...TEST!
- LESSON 16: Percent Change - By What Percent Did the Value Change?
- LESSON 17: Percent Change - More Practice
- LESSON 18: Simple Interest - Understand Your Money!
- LESSON 19: All Percents Review
- LESSON 20: All Percents Test
- LESSON 21: Proportional Reasoning and Percent - Can you apply the concepts? (3 Day Lesson)