Tracy Rains
Mathematics, Algebra
Material Type:
Lesson Plan
Middle School, High School
Exploring Real Numbers, Iowa Video, Number Line, Rational and Irrational Numbers, iowa-video
Creative Commons Attribution-NonCommercial 4.0
Media Formats:
Downloadable docs, Interactive, Text/HTML, Video

Absolute Value

Absolute Value


In this seminar you will learn about the absolute value of numbers. You will learn how taking the absolute value affects both positive and negative numbers. You will use the techniques learned in this seminar to verify solutions to various other types of problems involving absolute value as you move forward. When looking at absolute value, you will identify how it can change a solution and the compare the difference that it makes in equations when there are multiple negative signs.



Apply properties of rational and irrational numbers to solve real world or mathematical problems

Learning Target

I can find the absolute value of a given number or numbers.

Habits of Mind


Critical Thinking Skill


Academic/Concept Vocabulary

  • Absolute value

  • Negative

  • Number line

  • Positive




Introductory warm-up activity.

This one may confuse you!  When is -8.25 “more than” -1.25?  Can you think of anywhere in math this could be true?  If you do, please share with a partner now. If you don’t, it is ok. This lesson will show you one case where it could be true.


Read or watch the resources to learn about this concept, then do the practice activity.




Click here to read about the topic of Absolute Value. Be sure to practice the 13 questions at the bottom once you have read through the material. Pay close attention to the examples involving subtraction or negative numbers. The rules with negatives are important to understand from the beginning. Make sure to write down a definition for absolute value and two examples you can refer to in your math notebook. Pick a positive number and negative number so you know how to find the absolute value of each. 

Click here for a  little deeper explanation about Absolute Value, including some additional examples. The main addition to what you previously read is it also includes comparing numbers using absolute value and a bit more on how the placement of negative signs can affect an answer.

Math Short Episode 10 is true to its name, as it is a short math video, but a perfect introduction (or reminder) of what Absolute Value is. Please click to watch it now. Take note of the example given of the girl walking a distance. Think about how you could see absolute value used in other math problems. Pick at least one example to put in your math notebook to refer to if needed moving forward.

Now take some time to watch this Absolute Value video to see it used in various problems from comparing numbers to ordering from least to greatest. The skills in this video will be put to use in various problems moving forward in math, so you want to pay close attention.  Remember to take notes as you watch!

See how well you understand the vocabulary surrounding Absolute Value by trying this Quizlet matching game. Tried it once? Do it again and see if you can beat your time!

After you have the vocabulary down, it’s time to try some problems by downloading this Absolute Value worksheet. You can check your answers once complete. Be careful with the problems involving negative signs.



Discuss your ideas / opinions / understandings.

What do you get for the absolute value of the following number?  -| -1234 |. Be sure to include what you think the answer would be and WHY. Act as if your answer is on trial and you are trying to sway the jury to believe it. They need to know the why of it.


Now it is time to self-check how much you have learned about this topic.  If you do not know as much as you thought, go back to the “Explore” section of this seminar and reread, rewatch, or redo the activities listed.  See your facilitator if you have questions.

Click here to take the quiz online. You do not have to log into the quiz site in order to take this quiz. If a window pops up asking you to sign up for the quiz site, just close the sign-up window and start your quiz.


This is a task or project where you can show what you know.

Picture this:  An airplane is flying 22,452 ft above sea level. A whale swims at a depth of -4,353 ft (below sea level).  What is the distance between the airplane and the whale? Did you know you are using absolute value to answer this problem? Can you see where you used it? Explain how it is used in this problem in a sentence or two.

After you have thought about the above problem, it is time to create some of your own. Your task in this section is to create 6 scenarios where absolute value will be used. Look for or create a photo or diagram to go with each of your questions. Also create an an answer key for each problem.

Need some help?  Watch this video for some ideas: Interpret Absolute Value in Real-World Situations



Complete this wrap-up activity where you reflect on your learning.  

What exactly is absolute value and why is it important to everyday situations?  What was one new thing you learned in this lesson that you hadn’t already known about absolute value?  How is it related to what you already knew? Use an example in your explanation if needed.