Lesson 1

Discover

 

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What is the distance between Edmonton and Calgary? How does your answer compare to the distance between Calgary and Edmonton? Is there a difference? Would you use negative, positive, or both kinds of values to describe distance? In this Discover section you will consider the answers to these questions by experimenting with an applet.

Try This 1

 

Part A: Investigating the Absolute Value of a Number

 

Launch the Absolute Value applet. After clicking to start the applet, you will notice that it has two panels: the left panel has a slider for a and the right one has a number line.

On the number line, click and drag the point marked by x to 0. Check the lower left side of the right panel to make sure that x = 0.0. Note the value of  and record it in a table like the one shown. This is the absolute value of x. (Both x and a should be at 0 to begin the activity.)

x		Value
0
2
−2
7
−7
4.3
−0.8

1. Complete the table by dragging the x on the number line to the other points shown in the table. Record your answers in the appropriate row.
   
   
2. Based on your observations, how would you instruct someone to determine the absolute value of a number?

Part B: Investigating the Absolute Value of an Expression

 

In the left panel, drag the appropriate slider so that a = 2

In the right panel, click and drag x to 5. Record the resulting expression for  (shown in the lower-left corner of the right panel) in a table like the one that follows

x	a		Value
5	2
−5	2
−3	−5
3	−5
−3	5
4	−4
−1	−6

3. Complete the table by dragging the x on the number line to the other points shown in the table. Record your answers in the appropriate row.
   
   
4. Based on your observations, how would you instruct someone to determine the absolute value of an expression?

Save your work in your course folder. You will confirm these results later in the lesson.