Practice and Problem-Solving Exercises

A Practice

See Problem 1.

Use a number line to find each sum.

10. 2 + 5
11. − 3 + 8 negative 3 plus 8
12. 4 + ( − 3 ) 4 plus open negative 3 close
13. 1 + ( − 6 ) 1 plus open negative 6 close
14. − 6 + 9 negative 6 plus 9
15. − 4 + 7 negative 4 plus 7
16. − 6 + ( − 8 ) negative 6 plus open negative 8 close
17. − 9 + ( − 3 ) negative 9 plus open negative 3 close

See Problem 2.

Find each sum.

18. 11 + 9
19. 17 + ( − 28 ) 17 plus open negative 28 close
20. 12 + ( − 9 ) 12 plus open negative 9 close
21. − 2 + 7 negative 2 plus 7
22. − 14 + ( − 10 ) negative 14 plus open negative 10 close
23. − 9 + ( − 2 ) negative 9 plus open negative 2 close
24. 3.2 + 1.4
25. 5.1 + ( − 0.7 ) 5.1 plus open negative 0.7 close
26. − 2.2 + ( − 3.8 ) negative 2.2 plus open negative 3.8 close
27. 1 2 + ( − 7 2 ) 1 half , plus . open , negative , 7 halves , close
28. − 2 3 + ( − 3 5 ) negative , 2 thirds , plus . open , negative , 3 fifths , close
29. 7 9 + ( − 5 12 ) 7 ninths , plus . open , negative , 5 twelfths , close

See Problem 3.

Find each difference.

30. 5 − 15 5 minus 15
31. − 13 − 7 negative 13 minus 7
32. − 19 − 7 negative 19 minus 7
33. 36 − ( − 12 ) 36 minus open negative 12 close
34. − 29 − ( − 11 ) negative 29 minus open negative 11 close
35. − 7 − ( − 5 ) negative 7 minus open negative 5 close
36. 8.5 − 7.6 8.5 minus 7.6
37. − 2.5 − 17.8 negative 2.5 minus , 17.8
38. − 2.9 − ( − 7.5 ) negative 2.9 minus open negative 7.5 close
39. 3.5 − 1.9 3.5 minus 1.9
40. 1 8 − 3 4 1 eighth , minus , 3 fourths
41. 7 16 − ( − 1 2 ) 7 sixteenths , minus . open , negative , 1 half , close

See Problem 4.

42. Bird Watching An eagle starts flying at an elevation of 42 ft. Elevation is the distance above sea level. The diagram below shows the elevation changes during the eagle's flight. Write an expression representing the eagle's flight. What is the elevation at the brook?

    

43. Stock Market A stock's starting price per share is $51.47 at the beginning of the week. During the week, the price changes by gaining $1.22, then losing $3.47, then losing $2.11, then losing $.98, and finally gaining $2.41. What is the ending stock price?

B Apply

Evaluate each expression for a = − 2 , b = − 4.1 , eh equals negative 2 comma b equals negative 4.1 comma  and c = 5.

44. a − b + c eh minus b plus c
45. − c + b − a negative c plus b minus eh
46. − a + ( − c ) negative eh plus open negative c close
47. Error Analysis Describe and correct the error in finding the difference shown below.

    

48. Writing Without calculating, tell which is greater, the sum of − 135 negative 135  and 257 or the sum of 135 and − 257 . negative 257 .  Explain your reasoning.

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