Lesson 15

Multiplying Rational Numbers

Let’s get more practice multiplying signed numbers.

Problem 1

Evaluate each expression:

  1. \(\text-1 \boldcdot 2 \boldcdot 3\)
  2. \(\text-1 \boldcdot (\text-2) \boldcdot 3\)
  3. \(\text-1 \boldcdot (\text-2) \boldcdot (\text-3)\)

Problem 2

Find the value of each expression.

  1. \(\frac14 \boldcdot (\text-12)\)
  2. \(\text{-}\frac {1}{3} \boldcdot 39\)
  3. \((\text{-}\frac {4}{5}) \boldcdot (\text-75)\)
  4. \(\text{-}\frac {2}{5} \boldcdot (\text{-}\frac {3}{4})\)
  5. \(\frac83 \boldcdot \text-42\)

Problem 3

Fill in the missing numbers in these equations

  1. \((\text-7)\boldcdot {?} = \text-14\)
  2. \({?}\boldcdot 3 = \text-15\)
  3. \({?}\boldcdot 4 = 32\)
  4. \(\text-49 \boldcdot 3 ={?}\)

Problem 4

These three points form a horizontal line: \((\text-3.5, 4)\), \((0, 4)\), and \((6.2, 4)\). Name two additional points that fall on this line.

(From Unit 7, Lesson 11.)

Problem 5

Order each set of numbers from least to greatest.

  1. 4, 8, -2, -6, 0
  2. -5, -5.2, 5.5, \(\text-5\frac12\), \(\frac {\text{-}5}{2}\)
(From Unit 7, Lesson 1.)

Problem 6

Decide whether each table could represent a proportional relationship. If the relationship could be proportional, what would be the constant of proportionality?

  1. Annie’s Attic is giving away $5 off coupons.

    original price sale price
    $15 $10
    $25 $20
    $35 $30

  2. Bettie's Boutique is having a 20% off sale.

    original price sale price
    $15 $12
    $25 $20
    $35 $28
(From Unit 5, Lesson 4.)