Combining Like Terms

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Objective

SWBAT simplify algebraic expressions by combining like terms.

Big Idea

Students will identify the parts of an expression using math terminology. Students will understand the concept of like terms with the use parallel examples.

Do-Now

10 minutes

Students will translate verbal phrases into algebraic expressions as a review from the previous day. During Combining Like Terms Do-Now, struggling learners will have the option to use vocabulary cards as an aid with unfamiliar words. 

Students will come up to the board and write their answers after 3 minutes.  

Next, a student will read the objective and question of the day to the class: SWBAT simplify expressions by combining like terms.

I will then call on a volunteer student and ask:

  • What does it mean if two things are alike? 
  • Does alike mean congruent or the same?

Direct Instruction + Guided Notes

35 minutes

Todays lesson lays the groundwork for solving equations, so it is crucial that students leave class with a firm understanding of like terms and the parts of an expression.

Using the Combining Like Terms presentation, the first three slides aim to bridge the work that was done during our last class. The next few slides provide students with the important algebraic vocabulary they will need for combining like terms and solving equations.

Slide 7

To introduce this slide, I will tell the class that I have three “challenge” questions for them to complete silently. Students will quickly realize the joke I am making when they see simplicity of the problems.  I will build on the class momentum and ask a few student volunteers to fully elaborate why 1 heart + 1 heart = 2 hearts, but 1 heart + 1 triangle ≠2 hearts and does not equal 2 triangles. Using our new vocabulary, I will tell students that for two terms to be alike in math, they must have the same variable and exponent. We can then add the coefficients using what we know about integers.

Slide 11

We will begin to combine like terms on slide 11. To help students visualize like terms, I will draw a circle around all constants, a square around all terms that have a coefficient of x, and a triangle around each x2 term.  

During this class a mini-session of the commutative property will be necessary. I will ask students if 3 – 4 is equal to 4 – 3 (students who struggle with integers, may need this exampled illustrated using integer chips). I will emphasize the sign of each term in every example by asking students to identify if it is positive or negative. I tell students to look for the +/- sign in front of a term because it "belongs" to it.

Students quickly understand like terms; The biggest hurdle in this lesson was integers, which many of my students still struggle with. To combat this, students will use red and write integer chips or a number line as they combine like terms to allow them to focus on the new skill.

Independent Practice - Art Activity

25 minutes

Students will practice combining like terms using this art activity. Each student will need colored pencils, markers, or crayons.

I will ask a student to reiterate the definition of a like term. I will then ask students to find a box on their paper that would could be considered a like term with “x”.  After they share their responses I instruct them to color “x” ,“3x”,“0.1x”, and the box they chose the same color because they fit the definition of a like term. I will ask a volunteer to use the definition of like terms to justify whether x2 and cx should be colored the same color a “x” “3x” and “0.1x”.

Students will complete the rest of this activity on their own, shading all like terms with the same color. I will ask students who finish early to begin creating expressions on the back of their paper with the like terms they colored.

Closing

10 minutes
I will ask two students to give a 15 second summary of what we learned in class today. I will ask a third student to share out one thing that makes this skill difficult, and one tip they would give a struggling student who was working on the same activity. Students will then complete combining like terms exit card.