2-2 Adding Integers
Find each sum.
9. –7 + (–3)
SOLUTION: Use a number line.
Start at zero.
Move 7 units to the left.
From there, move 3 more units to the left.
So, –7 + (–3) = –10.
10. –6 + (–14)
SOLUTION: Use a number line.
Start at zero.
Move 6 units to the left.
From there, move 14 more units to the left.
So, –6 + (–14) = –20.
11. 17 + (–8)
SOLUTION: Use a number line.
Start at zero.
Move 17 units to the right.
From there, move 8 units to the left.
So, 17 + (–8) = 9.
12. 21 + (–11)
SOLUTION: Use a number line.
Start at zero.
Move 21 units to the right.
From there, move 11 units to the left.
So, 21 + (–11) = 10.
13. 8 + (–13)
SOLUTION: Use a number line.
Start at zero.
Move 8 units to the right.
From there, move 13 units to the left.
So, 8 + (–13) = –5.
14. 12 + (–16)
SOLUTION: Use a number line.
Start at zero.
Move 12 units to the right.
From there, move 16 units to the left.
So, 12
+ (–16)
= –4.by Cognero
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15. 11 + (–5)
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2-2
Use a number line.
Start at zero.
Move 8 units to the right.
From
there,Integers
move 13 units to the left.
Adding
So, 8 + (–13) = –5.
14. 12 + (–16)
SOLUTION: Use a number line.
Start at zero.
Move 12 units to the right.
From there, move 16 units to the left.
So, 12 + (–16) = –4.
15. 11 + (–5)
SOLUTION: Use a number line.
Start at zero.
Move 11 units to the right.
From there, move 5 units to the left.
So, 11 + (–5) = 6.
16. 13 + (–2)
SOLUTION: Use a number line.
Start at zero.
Move 13 units to the right.
From there, move 2 units to the left.
So, 13 + (–2) = 11.
For Exercises 17 and 18, write an addition equation. Then solve.
17. FOOTBALL A football team gained 6 yards on a play. It then lost 10 yards on the next play. What was the total
change of yardage for the team?
SOLUTION: Let x represent the change of yardage.
The total change of yardage is –4 yards.
18. TEMPERATURE The temperature in Rockford, Illinois, was –3°F. The temperature rose 7 degrees. What is the current temperature?
SOLUTION: Let t represent the temperature.
The current temperature is 4˚F.
Find each sum.
19. 10 + (–3) + 3
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SOLUTION: Let t represent the temperature.
2-2 Adding Integers
The current temperature is 4˚F.
Find each sum.
19. 10 + (–3) + 3
SOLUTION: 20. –7 + (–1) + 7
SOLUTION: 21. –15 + 8 + (–9)
SOLUTION: 22. –6 + (–2) + 14
SOLUTION: 23. 8 + (–11) + (–19) + 11
SOLUTION: 24. 13 + 20 + (–17) + (–13)
SOLUTION: 25. HIKING Sally begins hiking at an elevation of 324 feet. Then, she descends to an elevation of 201 feet and climbs
to an elevation 55 feet higher than that which she first began. She then descends 183 feet. Describe the overall
change in elevation.
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SOLUTION: 2-2 Adding Integers
25. HIKING Sally begins hiking at an elevation of 324 feet. Then, she descends to an elevation of 201 feet and climbs
to an elevation 55 feet higher than that which she first began. She then descends 183 feet. Describe the overall
change in elevation.
SOLUTION: The overall change in elevation is –128 feet.
26. SHARKS Use the diagram shown.
The shark rises 68 feet from the depth shown. Then it descends another 25 feet. What is its current depth?
SOLUTION: The shark’s current depth is –60 feet.
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