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Instructor Overview

Students answer questions about low temperatures recorded in Barrow, Alaska, to understand when to use negative numbers and when to use the absolute values of numbers.

Key Concepts

  • The absolute value of a number is its distance from 0 on a number line.
  • The absolute value of a number n is written |n| and is read as “the absolute value of n.”
  • A number and the opposite of the number always have the same absolute value. As shown in the diagram, 
    |3| = 3 and |−3| = 3.
  • In general, taking the opposite of n changes the sign of n. For example, the opposite of 3 is –3.
  • In general, taking the absolute value of n gives a number, |n|, that is always positive unless n = 0. For example, |3| = 3 and |−3| = 3.
  • The absolute value of 0 is 0, which is neither positive nor negative: |0| = 0.

Goals and Learning Objectives

  • Understand when to talk about a number as negative and when to talk about the absolute value of a number.
  • Locate the absolute value of a and the absolute value of b on a number line that shows the location of a and b in different places in relation to 0.