Lesson 8

Money and Debts

Let's apply what we know about signed numbers to money.

Problem 1

The table shows five transactions and the resulting account balance in a bank account, except some numbers are missing. Fill in the missing numbers.

transaction amount account balance
transaction 1 200 200
transaction 2 -147 53
transaction 3 90
transaction 4 -229
transaction 5 0

Problem 2

  1. Clare has $54 in her bank account. A store credits her account with a $10 refund. How much does she now have in the bank?

  2. Mai's bank account is overdrawn by $60, which means her balance is -$60. She gets $85 for her birthday and deposits it into her account. How much does she now have in the bank?

  3. Tyler is overdrawn at the bank by $180. He gets $70 for his birthday and deposits it. What is his account balance now?

  4. Andre has $37 in his bank account and writes a check for $87. After the check has been cashed, what will the bank balance show?

Problem 3


  1. \(5\frac34 + (\text{-}\frac {1}{4})\)
  2. \(\text {-}\frac {2}{3} + \frac16\)
  3. \(\text{-}\frac {8}{5} + (\text{-}\frac {3}{4})\)
(From Unit 7, Lesson 7.)

Problem 4

Which is greater, \(\frac {\text{-}9}{20}\) or -0.5? Explain how you know. If you get stuck, consider plotting the numbers on a number line.

(From Unit 7, Lesson 2.)

Problem 5

Decide whether or not each equation represents a proportional relationship.

  1. Volume measured in cups (\(c\)) vs. the same volume measured in ounces (\(z\)): \(c = \frac18 z\)
  2. Area of a square (\(A\)) vs. the side length of the square (\(s\)): \(A = s^2\)
  3. Perimeter of an equilateral triangle (\(P\)) vs. the side length of the triangle (\(s\)): \(3s = P\)
  4. Length (\(L\)) vs. width (\(w\)) for a rectangle whose area is 60 square units: \(L = \frac{60}{w}\)
(From Unit 5, Lesson 5.)