Overview and Background

This lesson will meet the following standard:

CCSS.Math.Content.7.EE.A.1
Apply properties of operations as strategies to add, subtract, factor, and expand linear expressions with rational coefficients.

In this lesson students will learn how to add and subtract linear expressions with integer coefficients.

Lesson Plan and Activity

Start this activity by guiding students through an example. We want to add (2x+3) + (x+1). Show them how to set up these two expressions [Figure 1].

Next, have students count or group together all of the x’s to see that there are a total of three and do the same for the ones to see a total of four. They should write out the result as 3x + 4. Once they see how this works students can work on more examples on their own or in groups. Then, guide students through a subtraction example. To subtract (2x+3) – (x+1) take away from the first group the number of x’s and 1’s in the second. We are left with x + 2 [Figure 2].

See the files section for a handout.

Figure 1

Figure 2

Skills Learned

algebra

Duration of Lesson

one class period

Preparation

Print these manipulatives out a ahead of time. The amount you need to print will depend on how many students you have and if you want them to work in groups. If you want students to be able to add a lot of x's and 1's together you may want to print 30 of each per student/group.

Algebra: Adding and Subtracting Linear Expressions