<< Back to Lessons Index

7th Grade Math / Lesson 1: Absolute Values

ABSOLUTE VALUE
What will we be learning in this lesson?


  • This lesson will learn about absolute values.

    Vocabulary words are found in this purple color throughout the lesson. Remember to put these in your notebook.


ABSOLUTE VALUE


  • The absolute value of a number is the distance from zero.
  • The symbol ll represents absolute value.

    Examples: l6l The absolute value of 6 is asking - How far is 6 from zero?
        l6l = 6 it is 6 places from zero on a number line

    l-3.5l The absolute value of -3.5 is asking - How far is -3.5 from zero?
        l-3.5l = 3.5 it is 3.5 places from zero on a number line

  • Since absolute value is the distance that a number is from zero, it must always be a positive answer because distances can not be negative.


ABSOLUTE VALUE


  • Find the absolute values of the following.

    l13l

    l-6l

    l3.5l

    l-1.5l

    l1.5l


ABSOLUTE VALUE


  • Find the absolute values of the following.

    l13l=13

    l-6l= 6

    l3.5l= 3.5

    l-15l=15

    l1.5l=1.5


ABSOLUTE VALUE


  • What about the absolute value of an unknown?

          lxl = 4

  • This says that the absolute value of some number is 4. In other words, the distance from zero is 4.

  • What number, or numbers, are 4 spots from zero?

  • Since there is no indication as to which direction from zero, this actually has two answers. 4 and -4 are both 4 spots from zero. One to the right and one to the left.

  • So in this case, we say that x = 4 and -4


ABSOLUTE VALUE


  • Find the appropriate x-values for the following.

    lxl=13

    lxl= 6

    lxl= 3.5

    lxl= 15

    lxl= 1.5


ABSOLUTE VALUE


  • Find the appropriate x-values for the following.

    lxl=13      x = 13 or -13

    lxl= 6       x = 6 or -6

    lxl= 3.5    x = 3.5 or -3.5

    lxl= 15     x = 15 or -15

    lxl= 1.5    x = 1.5 or -1.5