Additive Inverse + Absolute Value

Introduction

After discussing the real number system, I venture into a discussion on additive inverse + absolute value. At a 7th grade level, both topics are pretty simplistic and don't take long to teach... so I like to combine them together into one lesson.

Notes

I use digital notes when teaching additive inverse + absolute value. The digital notes include a slide on additive Inverse with real-life application problem (i.e. Quentin was sacked for a loss of 6 yards and then gained 6 yards on the next play). The second slide discusses absolute value and more real-life application problems (i.e. Lisa has a balance of -$35 and Samantha has a balance of -$32. Use this information to answer the following: Which person has greater debt?

The digital notes also Include an analogy graphic I use to teach absolute value. It discusses how absolute value is like a washing machine. It doesn't matter if you put in dirty or clean clothes, the clothes will always come out clean.

The final slide of the notes includes a slide for students to practice the concept. A link to the notes + a copy of the washing machine analogy are shown below.

Activities

I have used a couple activities to help reinforce the concept of additive inverse + absolute value within my classroom. Here is a brief description of each:

1) Additive Inverse/Absolute Value Board Game: For this game, you will want to print out a game board + number values sheet for each team. Have the students cut out the various number values (or you can have this done in advance). Students put all of the values face down. They take turns select values from the pile. If the value negative, they have to move backwards that many spaces. If it is positive, they get to move forward. First player to make it to the finish… wins! :)

2) Match + Switch Activity: Students will need a pencil and an activity sheet to complete this activity. Cut out the individual number cards and give one to each student in the class (I would suggest laminating these cards, if possible). When the teacher says “go” have the student walk around the room and trade papers with their classmates. They need to continuously trade papers with several different classmates until the teacher says “stop.” I like to play a song while the students are trading papers, but it isn’t a requirement. After being instructed to stop, the students need to pair up with a classmate. They need to write their values in the boxes provided on the activity sheet. Together, the students need to determine which inequality symbol should be placed between the two boxes. Once an appropriate amount of time has been given, say “go” and the students begin switching again. The activity sheet has enough spaces for 24 rounds, but you don’t have to complete the whole sheet.

3) Gallery Walk Activity: For this activity, you will need the google slide (with questions), the google form (for students to check answers) and the PDF answer document (for students to show their work). I begin by printing enough answer documents for all students. This isn’t necessary, but it is nice for student work to be organized. Next, you will want to open the google form and create a shareable link. You will share this link AND the google slide with students. If you don’t want this activity to be digital, you can print each slide and post them around the room for a traditional gallery walk.

Students will access the questions from the google slide, show their work on the answer document and then check their answers on the google form. The google form will tell them if their answer is right or wrong, so they can make changes when necessary.

Many of the activities are available on my shared google drive. You can access the links below.