Lesson 14

Absolute Value Meaning

  • Let’s investigate absolute values.

14.1: Math Talk: Closest to Zero

For each pair of values, decide mentally which one has a value that is closer to 0.

\(\text{-}\frac{4}{5}\) or \(\frac{5}{4}\)

\(\frac{1}{12}\) or \(\frac{1}{14}\)

-0.001 or 0.0001

1.3 or \(\frac{4}{3}\)

14.2: What is Absolute Value?

  1. One of the lowest places in Europe is 23 feet below sea level. We can use “-23 feet” to describe its elevation, and “\(|\text{-}23|\) feet” to describe its vertical distance from sea level. In the context of elevation, what would each of the following numbers describe?
    1. 37 feet
    2. \(|37|\) feet
    3. -6 feet
    4. \(|\text{-}6|\) feet
  2. Water freezes at 0 degrees Celsius. For each pair of temperatures, which temperature is closest to the freezing point of water? Use absolute value to explain your reasoning.
    1. \(14^\circ \text{C}\) or \(\text{-} 15^\circ \text{C}\)
    2. \(\text{-} 5^\circ \text{C}\) or \(\text{-} 2^\circ \text{C}\)
    3. \(\text{-} 12^\circ \text{C}\) or \(18^\circ \text{C}\)

14.3: Absolute Value Expressions

Find the value of these expressions.

  1. \(|10-12|\)
  2. \(|\text{-}16 + 5|\)
  3. \(3|9 - 4|\)
  4. \(|8 - 10| - 16\)
  5. \(2|\text{-}13 - 2| + 18\)
  6. \(9 - |19 + 3|\)

Summary