## Loading...

# Evaluating Expressions

Lesson 2 of 13

## Objective: SWBAT write and evaluate numerical expressions when the variable is in multiple positions in an equation.

#### Warm Up

*7 min*

The warm-up is designed to get students thinking mathematically. In my classroom the warm up is something to tackle, but not become frustrated with. This is posted where students see it - daily - as they enter the class each day. Students are asked to spend at least “3 quiet minutes” working independently and then they may choose to turn and talk to a friend about their strategies.

This warm- up activity is called I wonder...

Today students begin to generate a list of questions about our school. The questions must have a math component, but students are reminded that math is part of almost anything - they just have to find it. Before students begin, I remind them that math questions about our school can include time, money, people, area and perimeter, etc. To make sure every student is included, I call on a few students to share examples of questions that come to mind.

Then I give the students 3 quiet minutes to list their thoughts. After 3 minutes they share their thinking with a neighbor, and we have a few share out to the group. These lists will remain in the students math journals. They can revisit these questions on their own. I will come back to these questions as an assigned "I wonder warm-up" within the next few days.

#### Resources

*expand content*

#### Launch

*5 min*

A numerical expression with variables can be intimidating. Helping students see the fun in the challenge is important. I start this lesson with a conversation that gets students interested in what we will learn about today, and also helps them appreciate the challenge. I want my students to know that hard math is fun math.

*Let's talk about codes for a few minutes. What is a code? Do any of you know or use any codes? Who else uses codes? *

I explain to students that mathematicians use codes all the time. Algebraic expressions are an example of one of these codes. Students use a resource to look up the meaning of algebraic expression choosing from their text book, other math text books, or use the dictionary. I ask a few to share the definition they find, then we create one to use as a class. *"An algebraic expression is an expression that has at least one variable". * I ask the students to write up an example of an algebraic expression on a scrap of paper and share with those around them.

I put a few examples of my own expressions on the board and ask the student to give it a thumbs up if it is an algebraic expression and a thumbs down if not. I start with simple expressions like 3 - c and then get more complex. Adding in examples with more than one operation. Finally, I challenge them with 10b. This triggers yesterdays discussion about representing multiplication when there is a variable.

One student creates a complex expression - (a + 9) x (d +16) - so I ask him to write it on the board. This is a tough code to crack. So we break it down into pieces together. Before we do, I explain that today we are going to practice writing and interpreting more expressions.

*Remember, you will have to be a detective and look for math clues to change "math talk" into English and English into "math talk". *

*expand content*

#### Guided Practice

*20 min*

As a class, we play the game Algebraic Expressions Millionaire, from Math-Play. I start with a think-a-loud to model how to use what you know about math to find clues to crack the code.

*The first step of cracking a code is not finding out the value of the variable. First, you must use all the clues you know to understand what the expression means. This game will help us practice finding clues to help us understand the meaning of different expressions. *

I use a gradual release approach to completing this game. After modeling solving a few algebraic expressions, have students work in their partner groups and take turns answering each question. Simply saying the answer is not enough, each student is expected to explain their approach and survey the class before clicking the answer.

Note:

• This is an appropriate time to review the properties of addition and multiplication.

*expand content*

#### Now You Try It

*20 min*

Students work with their color group (color groups are homogeneous by ability) to write and interpret algebraic expressions.

I set the expectation before they begin. *"While you are working, I am going to be coming around and listening to your discussions. You and your partners should be talking about the clues that you can find, before you write the algebraic expression. These are going to be a bit tougher than the game, because you do not have multiple choices... so use your group members for support."*

When we work in color groups, I know each group will have different needs during this lesson. I circulate around the room and add challenges and supports as needed. There are 4 color groups. These groups are fluid, they are reassigned periodically based on topic, concept and student performance.

1 - These students need more support. I start with them, to help make sense of the directions and also to facilitate the discussion around the first question. Today, I stay with this group for the first 3 questions to ensure the discussion is math based.

2 and 3 - These groups are able to answer the questions based on the directions, but need support in organizing their thinking about the clues that help them solve the problem.

4 - This group needs an additional challenge. I encourage them to extend their understanding by writing their own phrases to create a round of "Numerical Expressions Millionaire", this time writing the algebraic expression and providing choices using English phrases.

*expand content*

#### Group Share

*5 min*

I bring the students back to their own seats for a group share. I typically ask the same question. * "Did any group have an interesting mathematical argument, discussion, or discovery?"*

At this time, one student from each group shares their experience to help bring the class back as a whole. We answer any questions and clarify any misunderstanding. If students make a mistake and learn from it, we share this too.

Today's group share focuses on one group who had a mathematical argument about one of their problems. The question asked them to write the algebraic expression for *5 less than the product of 6 and 3.*

Sometimes, the English language can be a barrier to understanding the math.

*expand content*

#### Ticket Out

*5 min*

I close with an assessment to test where everyone is at, after this lesson. Students independently solve the following problem that is posted on the board.

*Write an expression to show:*

*1/2 of 10 more than the number of wheels on w 18 - wheelers.*

*expand content*

Brandon,

Thank you for this feedback. For the Vo-Back-Ulary resource, I ask students to hold on to this handout throughout the unit. When we work with their word, they revisit this sheet and complete the bottom portion. This part essentially is asking that they explain how their word fits with the other words on this list. This activity helps the students make connections between the word they have been focusing on and the other words on the list.

For the ticket out, we decided that (18w) would represent the number of wheels on w 18- wheelers. So 10 more than that would be (18w + 10) to find 1/2 of that, students could multiply by 1/2 or .5 or divide by 2 (depending on their knowledge at this time of year).

I appreciate your suggestions about tiered worksheets. I usually have different leveled questions available on each of the handouts. I will assign students to work on different problems first, based on the level of support/ scaffolding they need, rather than work on different sheets entirely. When I provide modifications I usually adjust within the assignment, rather than the assignment itself.

I will try to add more details about the questions I ask my students to help them expand their thinking. Thank you for the suggestions and comments.

Julie

| 2 years ago | Reply

Julie,

I love your lessons, especially how you allow students to grapple with concepts and ideas to build understanding. I had several questions that I wanted to address after looking over the first two lessons.

1. In the vo-back-ulary game, how are students expected to fill out the bottom of the vocab sheet? ......is on the list because____________. I wasn't sure how to use this resource.

2. What was the actual answer to the exit ticket from day 2? I was slightly confused by the wording, I guess I am not a master code cracker

Recommendation

Could you add tiered worksheets that you might give to students for the independent practice. Also during the launch and gudied practice I would love to see some of the examples that you use to expand students thinking.

Thanks.

Brandon Johnson

| 2 years ago | Reply##### Similar Lessons

Environment: Urban

Environment: Urban

###### Using Order of Operations & Parentheses

*Favorites(8)*

*Resources(15)*

Environment: Rural

- LESSON 1: Numerical Expressions and Patterns Introduction Lesson
- LESSON 2: Evaluating Expressions
- LESSON 3: Revisiting Day
- LESSON 4: Strength of Operations
- LESSON 5: PEMDAS PIZZA
- LESSON 6: Order of Operations
- LESSON 7: Order of Operations & Decimals
- LESSON 8: What is the 100th Step?
- LESSON 9: Relationships & Rules
- LESSON 10: Graphing Patterns
- LESSON 11: The Challenge of Directions
- LESSON 12: Choice Time Continued
- LESSON 13: Write About Math the Way You Talk About Math