Basic Mathematics for College Students

94. GIN RUMMY After a losing round,
    a card player must deduct the value
    of each of the cards left in his hand
    from his previous point total of 21. If
    face cards are counted as 10 points,
    what is his new score?


95. FOOTBALL A college football team records the
    outcome of each of its plays during a game on a
    stat sheet. Find the net gain (or loss) after the third
    play.


96. SCUBA DIVING A diver jumps from his boat into
    the water and descends to a depth of 50 feet. He
    pauses to check his equipment and then descends
    an additional 70 feet. Use a signed number to
    represent the diver’s final depth.


97. GEOGRAPHY Death Valley, California, is the
    lowest land point in the United States, at 282 feet
    below sea level. The lowest land point on the Earth
    is the Dead Sea, which is 1,348 feet below sea level.
    How much lower is the Dead Sea than Death
    Valley?


98. HISTORY Two of the greatest Greek
    mathematicians were Archimedes (287–212 B.C.)
    and Pythagoras (569–500 B.C.).
    a. Express the year of Archimedes’ birth as a
    negative number.
    b. Express the year of Pythagoras’ birth as a negative
    number.
    c. How many years apart were they born?


99. AMPERAGE During normal operation, the
    ammeter on a car reads. If the headlights are
    turned on, they lower the ammeter reading 7 amps.
    If the radio is turned on, it lowers the reading
    6 amps. What number will the ammeter register if
    they are both turned on?

 5

Evaluate each expression.See Example 4.

Evaluate each expression.See Example 5.

Use a calculator to perform each subtraction.See Using Your
Calculator.

TRY IT YOURSELF

Evaluate each expression.

61. 
    
    
    
    62. 
        
    
    
    
    


62. 
    

    Subtract from 7. 64. Subtract 8 from.

    
    


63. 
    
    
    
    66. 
        
    
    
    
    


64. 
    
    
    
    68. 
        
    
    
    
    


65. 
    
    
    
    70. 
        
    
    
    
    


66. 
    
    
    
    72. 
        
    
    
    
    


67. 
    
    
    
    74. 
        
    
    
    
    


68. 
    


69. 
    


70. 
    


71. 
    


72. 
    

    Subtract from.

    
    


73. 
    

    Subtract from.

    
    


74. 
    
    
    
    82. 
        
    
    
    
    


75. 
    
    
    
    84. 
        
    
    
    
    


76. 
    
    
    
    86. 
        
    
    
    
    


77. 
    
    
    
    88. 
        
    
    
    
    

APPLICATIONS

Use signed numbers to solve each problem.

89. SUBMARINES A submarine was traveling
    2,000 feet below the ocean’s surface when the radar
    system warned of a possible collision with another
    sub. The captain ordered the navigator to dive an
    additional 200 feet and then level off. Find the depth
    of the submarine after the dive.

( 6 5) 3 (11) ( 2 1) 5 (19)

4 (4)  3  3

 8 [4(6)]  1 [5(2)]

 3 (3)  5 (5)

 4  9

 6  10

[ 5 (4)](2) 22

[ 4 (8)](6) 15

(8)(33) 7 (21)

(9)(20) 14 (3)

 3  3  3  1  1  1

 5 (4)  9 (1)

(64)(12) (53)(46)

0 (5) 0  8

 2 (10)  6 (12)

 3  2

5  9 (7) 6  8 (4)

 979 (44,879)  787 1,654(232)

1,557 890 20,007(496)

(1)(52) 4 (21)

(3)(41) 7 (19)

(2)(30) 3 (66)

(5)(15) 6 (48)

 8 (412)  9 (110)

 9 (67)  13 (612)

 42 ( 16 14)  45 ( 8 32)

 1 ( 4 6)  7 ( 2 14)

 5  8 (3)  6  5 (1)

 1 (3) 4  2  4 (1)

2.3 Subtracting Integers 163

− 10 −^55

− 15

− 20

10

15

• 
  
  
  
  • 20
  
  
  
  

(^8) J J
J
9
2
2
Down Play Result
1st Run Lost 1 yd
2nd Pass—sack! Lost 6 yd
Penalty Delay of game Lost 5 yd
3rd Pass Gained 8 yd