Lesson 2 of 9
Objective: SWBAT find the absolute value of an integer.
To bring students into the lesson, I will share a story, "hook".
When I was about your age, I was given a lot of responsibility. My mother used to arrive home from work later than me, so I was supposed to have a snack and begin my homework. I was not supposed to watch tv, call friends, or leave the house.
One day, I finished my homework early and I knew my mother wouldn't be home for a few hours. I decided to go over to a friend's house nearby. Although I knew I wasn't allowed to, I rode my bike to her house. About a half hour later, the doorbell rings. My mother was at the door. She was driving by on her way home and recognized my bicycle in the driveway. She ordered me home immediately and I knew I was in trouble.
I was grounded for a few weeks, which meant I wasn't allowed to visit any friends, talk on the phone, or watch tv. It felt like I was in jail.
After a few weeks, my punishment was over and was "released from jail". I was absolutely, positively happy.
** Note: I always emphasize the difference between my silly math words and the correct math vocabulary. Students need to learn how to use the appropriate vocabulary.
Continuing from the hook, I will explain how numbers are sometimes in "jail". When these numbers are released they are absolutely positive.
Ex. 1 - |4| = 4|-4| = 4
For the first example, I will explain how both 4 and -4 are in jail and when they are released they both become positive 4.
Before introducing more examples, I will discuss with students the real meaning of absolute value.
Absolute Value - the distance between a number and zero on a number line
How far is 4 from 0 on a number line? How far is -4 from 0 on a number line? When we talk about distance, will distance be negative? Have you ever heard someone say, "I'm so tired, I just walked negative five miles"?
We will review a few more examples as a class.
Ex. 2 - Evaluate |-28| - |6|
Ex. 3 - Evaluate |33 - 2|
Students will be given 10 minutes to complete absolute value problems.
Give the absolute value of the integer.
4)|160 - 24|
6)|-1| + |34| + |-62|
7)|99 - 28|
8)|-36| - |-4|
After 10 minutes, I will randomly call students to the board to share their answers and reasoning with the class.
I will answer any questions regarding absolute value. I will pose the question:
What is the absolute value of 0?
Allow students time to think about what this question is asking and let them arrive at the answer themselves.