2.1 Writing Decimals 1. 0.8
2. 40
3. 0.006
4. 0.0009
5. 0.59
6. 3.008
7. 0.000275
8. 0.00063
9. 0.09
10. 0.004
11. 0.3
12. 0.0002
13. c
14. e
15. a
16. b
17. f
18. d
19. 8.57
Section 2.1 21. 0.036
22. 6.0031
23. 0.8432
24. 900.6051
25. 1(10) + 8(1) + 2(0.01) + 5(0.001)
26. 4(0.1) + 3(0.01) + 2(0.001)
27. 1(100) + 3(10) + 4(0.01)
28. 2(10) + 3(1) + 9(0.1) + 8(0.001) + 4(0.0001)
29. 5(101) + 2(100) + 7 12
10
+ 1 13
10
30. 4 11
10
+ 6 2
1 10
+ 1 3
1 10
+ 9 15
10
31. 9(102) + 4(100) + 2 12
10
+ 8 13
Section 2.1 32. 6(100) + 1 11
10
+ 5 3
1 10
33. 0.24, 0.240
34. 8.4, 8.400
35. 14.0000903
36. 0.000040018
37. 70.9064
38. 3.050082
39. 4,000.740009
40. Amount of Salt Power of 10 Number of Grains
pinch 103 1,000
1
4 teaspoon 10 4
10,000
tablespoon 105 100,000
1
2 cup
106 1,000,000
41. 40,000
Section 2.1 43. 500,000
44. 2,700
45. 5 × 5 × 5 × 5 × 5 × 5 × 5
46. nine cubed
47. 46,000,000
48. 512
49. 1
50. 0
51. 500
52. 58
2.2 Comparing and Rounding
1.
2.
3.
4. 7.3
5. 1.684
6. 0.3
7. 0.001
8. 506
9. 2.2
10. 80.01
11. 75
12. 4.0
13. 63.33
14. 4.000
15. 0.10
16. >
17. =
Section 2.2
19. >
20. <
21. >
22. >
23. <
24. 0.475
25. 0.3080
26. 4.158
27. 8.47
28. 347.2
29. 347.151
30. 347.1509
31. 350
32. 347
33. 300
34. 0.526, 0.562, 0.565
35. 0.3528, 0.3534, 0.3546
36. 0.082, 0.825, 0.8251
37. 0.2027, 0.23, 0.253
38. 2.045, 2.04, 2.005
39. 2.93, 2.9, 2.5, 2.39
40. 7.340, 7.304, 7.043, 7.034
Section 2.2
42. Rogers
43. Guntle
44. 28.1
45. 52.00
46. >
47. =
48. >
49. <
50. <
51. 6(103) + 1(102) + 9(100)
52. 3(106) + 4(104) + 2(103) + 7(100)
53. 8(100) + 2 12
10
+ 3 3
1 10
54. 3 11
10
+ 4 2
1 10
+ 7 4
1 10
55. 11
56. 10
57. 8
58. 15
59. 140
2.3 Addition and Subtraction 1. 12.91
2. 5.981
3. $66.02
4. 0.9295
5. 57.7
6. 0.286
7. 1.821
8. 41.27
9. $233.78
10. 124.022
11. 134.846
12. 13.0961
13. 543.1
14. 35.67
15. 0.0269
16. 3.4862
17. $42.39
18. $38.05
19. $79.41
Section 2.3 21. 205.2
22. 6.391
23. $32.42
24. 95.8085
25. $781.42
26. 4.567
27. 138.195
28. 14.65
29. 8,246.953
30. 45.45
31. 17.913
32. 1.235
33. $76.97
34. 0.00682
35. 56.62
36. $12,549.50
37. 21.7
38. 193.8
39. $32.39
40. 4.838
41. 9.12
Section 2.3 43. 4.227 min.
44. 263.6 sec.
45. 3.897 mi./hr.
46. 0.758 mi./hr.
47. 2.5 + 6.35 + 8.1
48. 0.75 + 6.35 + 8.2
49. 0.625 + 7.5 + 3.25
50. 6.25 + 1.125 + 2.625
51. 9.85 + 0.525 + 0.625
52. 900
53. 20
54. 21,000
55. 2,400
56. 13,000
57. 1,500
58. 0.98, 0.980
59. 0.03, 0.030
60. 3.4, 3.40
2.4 Multiplication 1. 19.38
2. 0.987
3. 3.4204
4. 9.15938
5. 0.00948
6. 0.0756
7. 0.068
8. 0.000294
9. 3.36
10. 15.5904
11. 2.052
12. 1,814.76
13. 20.18307
14. 0.0776
15. 0.0602
16. 0.0185
17. 0.387
18. 0.0552
19. 0.033924
20. 3.6036
21. 0.00204
Section 2.4
23. 321.75
24. 0.022572
25. 2.435
26. 6.6572
27. 2.3112
28. 702
29. 54.288
30. 3.41251
31. 0.0138
32. 197.6836
33. 0.4225
34. 3.90847
35. 116.188
36. 32.768
37. 2.4225
38. 0.06636
39. 0.00822
40. 0.3696
41. $0.2192 ≈ $0.22
42. $2.211 ≈ $2.21
43. $3.4615 ≈ $3.46
Section 2.4
45. 395.64 mi.
46. 18.33 mi.
47. $0.08
48. $0.67
49. 1,169.64
50. 5,451.776
51. $2,376.15
52. $2.26
53. $24.80
54. 1.5 mm2
55. 0.125 mm3
56. 1,432; 1,423; 1,243; 1,234
57. 0.987, 0.978, 0.879
58. 6.42, 6.24, 4.62, 4.26
59. 757, 751, 715
60. 258.4
61. 258.370
62. 260
63. 300
64. 258.3698
2.5 Division 1. 9.5
2. $1.76
3. 6.15
4. 0.09
5. 42.67
6. 0.067
7. 6.3
8. 21.6
9. 38.85
10. 437
11. 2.6
12. 3.245
13. 3.5
14. $3.24
15. 117
16. 0.75
17. 1.875
18. 1.42
19. 350
Section 2.5 21. 1,200
22. 0.086
23. 6,000
24. 52
25. 16
26. 1.66 ≈ 1.7
27. 2.17 ≈ 2.2
28. 1.44 ≈ 1.4
29. 1.34 ≈ 1.3
30. 2.366 ≈ 2.37
31. 1.042 ≈ 1.04
32. 0.764 ≈ 0.76
33. 2.742 ≈ 2.74
34. 2.6666 ≈ 2.667
35. 0.5714 ≈ 0.571
36. 1.3142 ≈ 1.314
37. 1.3076 ≈ 1.308
38. $3.983 ≈ $3.98
39. $0.217 ≈ $0.22
40. $2.802 ≈ $2.80
Section 2.5 42. 15.6 mi./hr.
43. 13.4 mi.
44. $0.17
45. $3.58
46. 22.8 mi./gal.
47. 1,338.4 mi.
48. <
49. =
50. <
51. >
52. 0.00375 mm2
53. 0.0822 mg, or ≈ 0.1 mg
54. <
55. >
56. >
57. <
58. =
59. <
2.6 Estimating 1. 4
2. 10
3. $20
4. 11
5. 100
6. $60
7. 160
8. 450
9. 30
10. $9
11. 100
12. 12
13. 40
14. 60
15. 45
16. 10
17. b
18. a
19. c
20. b
21. 58.1
Section 2.6
23. 64.31
24. 24.9
25. 600
26. 9,000
27. 450
28. 360
29. 42
30. 540
31. $400; $460
32. 600; 730
33. 400; 390
34. 900; 1,080
35. $110; $125
36. 39; 40.6
37. 6,400; 6,780
38. 75; 75.2
39. >
40. <
41. <
42. >
43. $69
Section 2.6
45. 125 g or 150 g
46. 60 g
47. $18 or $20
48. $6
49. yes
50. 550 for $9.95;
Explanations will vary.
51. Answers will vary.
52. $720
53. a half-gallon for $4.89; Explanations will vary.
54. at least 30 cans; < $2
55. 8.62
56. 967.64
57. 1.47
58. 28.4
59. 0.96
60. 51.54
61. 0.0208
62. 13.653
63. $195.50
Problem Solving 2—Make a Table 1–2. Answers will vary.
3. 3 quarters, 7 dimes
4. Patriots (12 to 11)
5. 6
6. 12
7. 6
2.7 Square Roots 1. 6 and 7
2. 5 and 6
3. 10 and 11
4. 8 and 9
5. 2 and 3
6. 4 and 5
7. 6
8. 11
9. 9
10. 13
11. 3
12. 4
13. b
14. a
15. a
16. b
17. b
18. a
Section 2.7 20.
133
21.
22.
23.
24.
25. 24
26. 108
27. 84
28. 63
29. 18
30. 50
31. 28
32. 135
33. 132
34. 75
35. 36
36. 70
Section 2.7 38. 27
39. 7
40. 168
41. Underestimate; both
rounded whole numbers are lower than the actual square roots.
42. $0.84
43. $9.12
44. $16.77
45. $0.06
46. $0.25
47. $1,285.90
48. Commutative Property of Addition
49. Identity Property of Multiplication
50. Associative Property of Multiplication
2.8 Scientific Notation 1. 102
2. 104
3. 101
4. 105
5. 28.3
6. 4,650
7. 653.1
8. 0.0369
9. 74
10. 0.183
11. 0.762
12. 0.0009
13. 3
14. 5
15. 2.5
16. 7.062
17. $7
18. $14,500
19. $28.90
Section 2.8 21. 104,000
22. 6,183
23. 0.10071
24. 0.00062
25. 0.00006
26. 0.012
27. 6,015,000
28. 12.24
29. 7 × 103
30. 3.069 × 105
31. 2.87 × 105
32. 5.4 × 103
33. 5 × 106
34. 6.5 × 107
35. 1.3 × 105
36. 8.8 × 107
37. 4 × 109
38. c
39. b
40. a
41. 5,000
Section 2.8 43. 306,000
44. 92,000
45. 4,200,000
46. 6,980,000
47. 86,710,000
48. 376,000,000
49. 2,000,000,000
50. $3.75
51. $68.90
52. 1.6 × 109 km
53. 480,000 km
54. No; the first factor is not between 1 and 10.
55. 356
56. 4.7
57. The number of zeros in the factor you multiply by minus the number of
zeros in the number you divide by is equal to the final number of decimal places moved.
58. Each place in the decimal system represents a
Section 2.8 59. 7,370,000 grains
60. 38
61. 9
62. 26
63. 700
64. 70
65. 240
66. 2,000
67. 227
68. $10
2.9 Operations in Scientific Notation 1. 9.093 × 103
2. 3.45 × 106
3. 4.7 × 102
4. 1.255 × 107
5. 1.9 × 1012
6. 8.61 × 105
7. 106
8. 108
9. 107
10. 3.381 × 102
11. 7.98 × 105
12. 1.37 × 105
13. 1.175 × 104
14. 1.0012 × 107
15. 1.976 × 103
16. b
17. a
18. b
19. c
Section 2.9 21. 2.4 × 109
22. 2.76 × 105
23. 2.075 × 1010
24. 6.227 × 108
25. 2.352 × 1010
26. 3.168 × 108
27. 3.24 × 1011
28. 1.728 × 107
29. 2.6448 × 1011
30. 2.0727 × 1012
31. 6 × 1011
32. 1.375 × 1012 m
33. 1.197 × 1011 m
34. 3.99 × 1013 m
35. 1.8 × 103
36. 6 × 103
37. 2.88 × 104
38. 9.116 × 107
39. 8 × 1010 lb.
Section 2.9 41. 1.56 × 109 tn.
42. 3.2 × 107 yr.
43. about 4.5 × 109 yr.
44. the Flood; no
45. 9.14
46. 4.2
47. 8
48. 0.8
49. 1.667
50. 1.65
51. 8 and 9
52. 14 and 15
53. 4 and 5
Math and Scripture 2 1. all their increase
(produce)
2. no, also seed (produce) and livestock
3. the Levites
4. a tithe of the tithes of the people; 0.01
5. not tithing
6. a curse
7. blessings, rebuking the devourer, other nations would notice
8. fasting and tithing
9. mercy
10. the publican, because he humbled himself
11. no
12. Melchizedek
13. Levi
Chapter 2 Review 1. 5.184
2. 0.0019
3. 0.0481
4. 7.309
5. 4(100) + 2 1 10
+ 9 3
1 10
6. 6 12 10
+ 5 3
1 10 +
4 14 10
7. >
8. <
9. 0.434, 0.437, 0.473
10. 6.025, 6.052, 6.205, 6.250
11. 428.3
12. 428
13. 428.25
14. 428.251
15. 4.973
16. 137.7291
17. 531.1
Chapter 2 Review
19. 13.923
20. 34.64
21. 304.029
22. $217.48
23. 1.856
24. 128.216
25. 0.053014
26. 24.9
27. 0.604
28. 2.46
29. $1,620
30. 1.59
31. 3.9
32. 38.1
33. 0.03816
34. 0.0009
35. 1.9
36. 2.68
37. 0.765
38. $12
39. 530
Chapter 2 Review
41. 70
42. 30
43. 100
44. 5
45. 8
46. 15
47. 140
48.
49.
50. 3.7 × 104
51. 8.025 × 106
52. 200,000
53. 426,000,000
54. 1.44 × 106
55. 1.42 × 105
56. 9.52 × 102
57. 1.68 × 109