The Meaning of Absolute Value

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Objective

SWBAT determine the meaning of absolute value.

Big Idea

What is the meaning of absolute value?

DO NOW

10 minutes

This problem will require students to use a number line to support the answer.  The questions for this problem ask about last place which means students need to understand that last place means the least number (SMP 1 and 2). The problem also asks about identifying opposites which is a prerequisite skill to using and understanding absolute value.  I chose this problem because students should be able to solve it independently with very little struggle.  Students that struggle will benefit from a reminder that a number line will be a useful tool to use. (SMP 4)

Absolute Value

20 minutes

During this time, I am going to walk students through what absolute value looks like, how to find it, and then how to interpret the meaning.  According to the common core definition, students need to know and interpret the meaning.  (For example, for an account balance of –30 dollars, write |–30| = 30 to describe the size of the debt in dollars.) or (recognize that an account balance less than –30 dollars represents a debt greater than 30 dollars).  I’m anticipating this to be difficult for students. In my mind, I’m going to explain to students that there is no such thing as a negative distance, negative time, negative money, however, we can use absolute value to describe this information. (SMP 2)

Practicing with absolute value

25 minutes

There are 3 problems that the students will be practicing with and we will do each problem together.  Students will work the problem out independently to start (SMP 1). After a certain amount of time, allow students to partner up and share/explore strategies and responses.(SMP 3) Bring the group back to discuss these strategies.  Do this for each problem.

 Problems 1 and 2 are nice to use because the students are encouraged to use a number line.  If they've had exposure to rational numbers on a number line, they should understand the placement.  If they have not had exposure, then I might make a number line for them to use so they don't spend an enormous amount of time creating one. 

Problem 3: the purpose of this activity is to get students to see the relative position of the numbers.  Our goal is to get them to deepen their understanding of absolute value.  They should be encouraged to use the number line to help strengthen that understanding. 

 

Students typically want to make the negative number positive and make the positive number negative when using absolute value.  The number line will help them see that we are looking at the distance from zero and that number is never negative. 

Problem #3 is an illustrative math problem.

Absolute Value Round table

20 minutes

Students will be working on an absolute value Roundtable. The problems chosen for the roundtable mimic the lesson for the day.  Problems begin with what absolute value is, then change to writing and interpreting absolute value and finally, the students will write the integer and express it in terms of its absolute value.  (SMP1,2,3,4,6)

Closure

10 minutes

Students will be writing about absolute value in the closure.  Their task is to explain to a fellow student that was missing for the day what absolute value is all about.  They should use visuals and examples in their writing.  This is a fun way for students to reflect on their understanding of what they learned today.  As a teacher, I will be walking around looking at what students are saying.  If students are struggling, I am going to suggest that they use their notes to assist with their writing.   If time permits, have students share their reflections with another student (SMP 3)