# 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.)