Evaluating Algebraic Expressions

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Objective

SWBAT solve algebraic expressions by properly using the order of operations when given the value of the variable

Big Idea

Express Yourself! Just make sure you follow all the rules.

Curriculum Reinforcer

5 minutes

The curriculum reinforcer, is a daily practice piece that is incorporated into almost every lesson to help my students to retain skills and conceptual understanding from earlier lessons. My strategy is to use Spiraled Review to help my students retain what they learned during the earlier part of the year. This will help me to keep mathematical concepts fresh in the students mind so that the knowledge of these concepts become a part of students' long term memories.

Engagement

5 minutes

In this opening, I will be reviewing vocabulary words such as coefficient, variable, term, expression, constant, and most importantly, evaluate. In fact, when I get to the word evaluate, which I will save for last, I will display its definition to the class.

Definition of Evaluate

  • 1. To find the value or amount of 
  • 2. To judge the worth of

In this lesson, I will show my students how the definition of evaluate aligns with the evaluating of expressions.

 

During the presentation of the definition of Evaluate and how this definition applies to the concept of evaluating expression, my students will be taking notes while listening attentively yet staying prepared to answer and/or ask questions.

Instruction & Teacher Modeling

10 minutes

Today, I will give instruction that will feed off of the previous lesson that dealt with order of operations. In today's lesson, my students will learn how to evaluate algebraic expressions. It is imperative that we review order of operations as when we are evaluating expressions, we will be doing the same as evaluating numerical expressions using the order of operations. To show my students how this lesson relates to the previous lesson, I will give them a numerical expression to evaluate. Then, I will take that same numerical expression and substitute several numbers for variables but, I will give those variables the values that I substituted them for. Using this demonstration, I will show my students how this lesson is not much different from the lesson where they learned how to evaluate numerical expressions. They will be able to see how they would use the same method to evaluate algebraic expressions as they would use to evaluate numerical expressions. In fact, that the only difference is that you must first substitute in the given values for each variable presented in the expression.

 

Try It Out

10 minutes

For the guided practice, I will provide my students with two algebraic expressions to evaluate. They will do this using pencil and paper but, when asked, they will hold up their answer on a dry erase paddle which will let me know who needs my assistance and who will be able to complete the independent practice portion of this lesson alone.

Independent Exploration

20 minutes

To practice evaluating algebraic expressions, I will give my students an worksheet to complete. This worksheet will contain 10 algebraic expressions to evaluate. The first 5 of the 10 problems will only involve whole numbers. The last 5 problems will require them to calculate using decimal quantities and fractions.

Closing Summary

20 minutes

To close out the lesson, the students will first check their papers. To do this, I will first select 10 students, giving each of those selected a large sticky note. When I hand them the sticky note, I will tell them which problem I want them to solve on that sticky note. After they have copied their solution to their specified problem, they will then go to the board to place their sticky note in the designated space on the white board. Once all 10 students have placed their solution on the board we will check all 10 problems for accuracy as a class. 

During this time of checking for accuracy, I will facilitate a discussion that will cultivate deeper understanding as it pertains to evaluating algebraic expressions and the order if operations.

Attached to this section is a picture of the large sticky notes that I am speaking of in this section. They are a great resource. In the picture I have placed a regular sticky note pad in light pink with the large sticky note pads along with chart paper so that you can see comparatively, the size of the large sticky notes. There is also a bright yellow colored large sticky note that is in between the size of the blue colored sticky notes and the bright pink colored sticky notes (I used all of those already). 

I love to use these in lieu of having 10 different students up at the board fighting for space. Or only sending a few students up at a time, which eats away at valuable time. This allows students to complete the work that they would do at the board, at their seat, then place their work on the board, allowing it to be big enough for everyone to see but not so big that you cannot fit 10 of them on the board. This is a great teacher product.