1. Mental Math
A Life Long Skill

2. Mental Math # 1 = = = =
5 x x x x 1 =
4 x x x 1000 = = = = =

3. Mental Math # 1
= 7343
= 9073
= 2454
= 4357
5 x x x x 1 = 5392
4 x x x 1000 = 5408 =
= 840
= 142
= 7520

4. Mental Math # 2 = = =
3 x x x x x 1 =
4 x x x 100 = = = = =

5. Mental Math # 2
= 3573
= 6703
= 2544 =
3 x x x x x 1 =
4 x x x 100 = 4502
= 525
= 1424
= 220
= 4760

6. Mental Math # 3 = = = =
3 x x x x 1 =
4 x x x 100 = = = = =

7. Mental Math # 3
= 7596 =
= 1084 =
3 x x x x 1 = 3962
4 x x x 100 =
= 205
= 2072 =
= 6070

8. Mental Math # 4 = = = =
5 x x x x 1 =
7 x x x 100 = = = = =

9. Mental Math # 4
= 6427 =
= 1043 =
5 x x x x 1 = 5372
7 x x x 100 = 87600
= 205
= 1642
= 5033
= 4076

10. Mental Math # 5 200 + 60 000 + 4 + 70 = 50 + 80 + 90 + 20 + 10 == =
6 x x x x 1 =
9 x x x x 10 =
9 + 7 = = = =

11. Mental Math # 5 =
= 250
= 4400
= 330
6 x x x x 1 = 6202
9 x x x x 10 =
9 + 7 = 16
= 160
= 146
= 460

12. Mental Math # 6 500 + 20 + 500 + 80 = 30 + 80 + 70 + 10 + 10 == =
8 x x x x 1 =
9 x x x 1000 =
7 + 5 = = = =

13. Mental Math # 6
= 1100
= 200
= 1430
= 3060
8 x x x x 1 = 8344
9 x x x 1000 =
7 + 5 = 12
= 120
= 132
= 367

14. Mental Math # 7 48 + 21 = 53 + 34 = 34 + 52 = 456 + 120 = 438 + 340 == = = = =

15. Mental Math # 7
= 69
= 87
= 86
= 576
= 778
= 939
= 631
= 498
= 786
= 925

16. Mental Math # 8 = = = = = = = = = =

17. Mental Math # 8
= 483
= 597
= 569
= 896
= 879
= 950
= 665
= 576
= 366
= 839

18. Mental Math # 9 = = = = = = = = = =

19. Mental Math # 9
= 997
= 349
= 549
= 997
= 988
= 382
= 631
= 848
= 758
= 830

20. Mental Math # 10 = = = = = = = =
9) =
10) =

21. Mental Math # 10
= 796
= 1041
= 459
= 778
= 367
= 987
= 900
= 800
9) = 598
10) = 333

22. Mental Math # 11 Five and three tenths =
Thirty two and four hundredths =
Seventy-seven thousandths =
Two hundred four and five hundredths =
Nine hundredths = = = =
9) (5 x 1) + (2 x 0.1) + (4 x 0.01) =
10) 3 x x 0.01 =

23. Mental Math # 11 Five and three tenths = 5.3
Thirty two and four hundredths = 32.04
Seventy-seven thousandths = 0.077
Two hundred four and five hundredths =
Nine hundredths = 0.09
= 4.2
= 35.97
= 200.8
9) (5 x 1) + (2 x 0.1) + (4 x 0.01) = 5.24
10) 3 x x 0.01 =

24. Mental Math # 12 Nine and three hundredths =
Thirty two and four tenths =
Seven thousandths =
Three hundred and fifteen thousandths =
Nine hundredths = = = =
9) (5 x 0.001) + (2 x 0.01) + (4 x 0.1) =
10) 3 x x x 1 =

25. Mental Math # 12 Nine and three hundredths = 9.03
Thirty two and four tenths = 32.4
Seven thousandths = 0.007
Three hundred and fifteen thousandths =
Nine hundredths = 0.09
= 5.26 =
= 23.08
9) (5 x 0.001) + (2 x 0.01) + (4 x 0.1) = 0.425
10) 3 x x x 1 = 304.6

26. Mental Math # 13 1)

27. 2)

28. 3)

29. 4)

30. 5)

31. 6)

32. 7)

33. 8)

34. 9)

35. 10)

36. Mental Math # 13 1)
One and
four tenths or 1.4

37. 2)
Fifty-three
hundredths or 0.53

38. 3)
One and three
hundredths or 1.03

39. 4)
One and
Two tenths or 1.2

40. 5)
One and thirty-four
thousandths or
1. 034

41. 6)
Five thousandths or 0.005

42. One and thirteen thousandths or 1.0137)
One and thirteen thousandths or 1.013

43. Two and one hundred forty-two thousandths or 2.1428)
Two and one hundred forty-two thousandths or 2.142

44. Twenty-two thousandths or 0.0229)
Twenty-two thousandths or 0.022

45. One and five hundredths or 1.05
10)
One and five hundredths or 1.05

46. Mental Math # 14
or 3.5 or
0.98 or =
98.9 or
or =
6.6 or 6.60
Two hundredths or two thousandths =
1.9 or 0.999
1 or =
636 or 663 =

47. Mental Math # 14
or 3.5 or
0.98 or 0.89
98.9 or or
6.6 or 6.60
Two hundredths or two thousandths
1.9 or 0.999
1 or 0.95
636 or 663

48. Mental Math # 15 3.25 rounded to the nearest tenth =
234.9 rounded to the nearest whole number =
1.984 rounded to the nearest hundredth =
48.9 rounded to the nearest ten =
10.08 rounded to the nearest tenth =
6.6 rounded to the nearest whole number =
rounded to the nearest hundred =
7.3 rounded to the nearest whole number =
rounded to the nearest thousandths =
1.95 rounded to the nearest tenth =

49. Mental Math # 15 3.25 rounded to the nearest tenth = 3.3
234.9 rounded to the nearest whole number = 235
1.984 rounded to the nearest hundredth = 1.98
48.9 rounded to the nearest ten = 50
10.08 rounded to the nearest tenth = 10.1
6.6 rounded to the nearest whole number = 7
rounded to the nearest hundred = 1500
7.3 rounded to the nearest whole number = 7
rounded to the nearest thousandths = 0.654
1.95 rounded to the nearest tenth = 2

50. Mental Math # 16 10 x 30 = 3 x 500 = 2.4 x 2 = 5 x 80 = 100 x 38 =

51. Mental Math # 16
10 x 30 = 300
3 x 500 = 1500
2.4 x 2 = 4.8
5 x 80 = 400
100 x 38 = 3800
6.2 x 2 = 12.4
90 x 50 = 4500
300 x 20 = 6000
10 x 96 = 960
1.25 x 3 = 3.75

52. Mental Math # 17 100 x 93 = 30 x 70 = 0.9 x 2 = 50 x 60 = 1 x 3.8 =

53. Mental Math # 17
100 x 93 = 9300
30 x 70 = 2100
0.9 x 2 = 1.8
50 x 60 = 3000
1 x 3.8 = 3.8
10 x 3.8 = 38
200 x 50 =
30 x 40 = 1200
10 x 180 = 1800
1.99 x 2 = 3.98

54. Mental Math # 18 30 x 90 = 5 x $9.13 = 3 x $7.97 = 7 x $2.06 =

55. Mental Math # 18 30 x 90 = 2700 5 x $9.13 = $45 3 x $7.97 = $24
7 x $2.06 = $14 or 14.42
$5.13 x 6 = $30
5 x 3.89 = $20
10 x 3.8 = $38
300 x 50 =
10 x 340 = 3400
$1.98 x 2 = $3.96 or $4.00

56. Mental Math # 19 20 x 700 = 9 x $4.21 = 9 x $0.97 = 5 x $3.36 =

57. Mental Math # 19 20 x 700 = 14 000 9 x $4.21 = $36 9 x $0.97 = $9
5 x 3.09 = $15 or 15.45
1 x 5.9 = 5.9
10 x 5.9 = 59
100 x 66 = 6600
$1.05 x 3 = $3.15 or $3.00

58. Mental Math # 20
10 x 7.5 =
0.9 x 10 =
100 x 0.97 =
10 x 3.36 =
5.13 x 100 =
100 x 30.9 =
10 x =
1000 x 5.9 =
6.6  10 =
1.05 x 10 =

59. Mental Math # 20
10 x 7.5 = 75
0.9 x 10 = 9
100 x 0.97 = 97
10 x 3.36 = 33.6
5.13 x 100 = 513
100 x 30.9 = 3090
10 x = 0.18
1000 x 5.9 = 5900
6.6  10 = 0.66
1.05 x 10 = 10.5

60. Mental Math # 21
100 x 39.1 =
9.3 x 10 =
10 x 0.93 =
100 x 6.3 =
3.4  10 =
5.13 x 10 =
10 x 30.9 =
10 x =
1000 x 0.5 =
10.5  100 =

61. Mental Math # 21
100 x 39.1 = 3910
9.3 x 10 = 93
10 x 0.93 = 9.3
100 x 6.3 = 630
3.4  10 = 0.34
5.13 x 10 = 51.3
10 x 30.9 = 309
10 x = 0.01
1000 x 0.5 = 500
10.5  100 = 0.105

62. Mental Math # 22
45.1  10 =
9.3  10 =
67  10 =
6.3  100 =
3400  100 =
51.3  10 =
10 x 39.1 =
413.1  100 =
2.5  1000 =
750.5  100 =

63. Mental Math # 22
45.1  10 = 4.51
9.3  10 = 0.93
67  10 = 6.7
6.3  100 = 0.063
3400  100 = 34
51.3  10 = 5.13
10 x 39.1 = 391
413.1  100 =4.131
2.5  1000 =
750.5  100 = 7.505

64. Mental Math # 23
83  100 =
4.7 x 10 =
69.2  10 =
16.3  100 =
30.4  10 =
933  10 =
10 x 92.1 =
4  1000 =
2.5  100 =
5.2  10 =

65. Mental Math # 23
83  100 = 0.83
4.7 x 10 = 47
69.2  10 = 6.92
16.3  100 = 0.163
30.4  10 = 3.04
933  10 = 93.3
10 x 92.1 = 921
4  1000 =0.004
2.5  100 = 0.025
5.2  10 = 0.52

66. Mental Math # 24 7.7  100 = 40 x 300 = 500 + 30 + 6000 + 2 = 6 + 8 == =
3 x x x 1 =
46.45 rounded to the nearest tenth =
Five hundred and four thousandths =
Which is larger 98.9 or =

67. Mental Math # 24
7.7  100 = 0.077
40 x 300 =
= 6532
6 + 8 = 14
= 164
= 653
3 x x x 1 = 6032
46.45 rounded to the nearest tenth = 46.5
Five hundred and four thousandths =
Which is larger 98.9 or = 98.9

68. Mental Math # 25 822.4  100 = 50 x 30 = 5 + 800 + 60 + 2000 = 7 + 5 ==
2 x $3.99=
3 x x x 1000 =
rounded to the nearest hundredth =
ten and thirteen thousandths = =

69. Mental Math # 25
822.4  100 = 8.224
50 x 30 = 1500
= 2865
7 + 5 = 12
= 342
2 x $3.99= $7.98
3 x x x 1000 = 2360
rounded to the nearest hundredth = 8.45
ten and thirteen thousandths =
= 1.04

70. Mental Math # 26 105 cm = ____ m 2 L = _____ mL 5000 m = _____ km
3.4 mm = _____ cm
90 mL = _____ L
600 g = _____ kg
1 mg = _____ g
3 km = _____ m
0.01 g = _____ mg
20 m = _____ cm

71. Mental Math # 26 105 cm = 1.05 m 2 L = 2000 mL 5000 m = 5 km
3.4 mm = 0.34 cm
90 mL = 0.09 L
600 g = 0.6 kg
1 mg = g
3 km = 3000 m
0.01 g = 10 mg
20 m = 2000 cm

72. Mental Math # 27 6 L = _____ mL 3700 m = _____km and _____m
59 km = _____ m
3.4 cm = _____mm
345 mL = _____L
69 mg = _____ g
1112 g = _____kg
9 km = _____ m
0.08 g = _____ mg
2160 m = _____ km and _____m

73. Mental Math # 27 6 L = 6000 mL 3700 m = 3 km and 700 m
59 km = m
3.4 cm = 34 mm
345 mL = L
69 mg = g
1112 g = kg
9 km = 9000 m
0.08 g = 80 mg
2160 m = 2 km and 160 m

74. Mental Math # 28 3900 mm = _____ m 4321 m = _____ km and _____ m
5900 mL = _____ L and _____ mL
47 cm = _____ mm
805 mL = _____ L
6 g = _____ mg
4 kg = _____ g
9 km = _____ hm
8 g = _____ dg
2002 m = _____ km and _____ m

75. Mental Math # 28 3900 mm = 3.9 m 4321 m = 4 km and 321 m
5900 mL = 5 L and 900 mL
47 cm = 470 mm
805 mL = L
6 g = 6000 mg
4 kg = 4000 g
9 km = 90 hm
8 g = 80 dg
2002 m = 2 km and 2 m

76. Mental Math Practice # 1 Have $10, spend $1.25 =

77. Mental Math Practice # 1 Have$10, spend $1.25 = $8.75

78. Mental Math Practice # 2 Have $10, spend $2.75 =

79. Mental Math Practice # 2 Have $10, spend $2.75 = $7.25

80. Mental Math # 29 Have $10, spend $2.80 = Have $10, spend $5.35 =

81. Mental Math # 29 Have $10, spend $2.80 = $7.20

82. Mental Math # 30 Have $10, spend $3.35 = Have $10, spend $7.40 =

83. Mental Math # 30 Have $10, spend $3.35 = $6.65

84. Mental Math # 31 Have $10, spend $8.30 = Have $10, spend $1.41 =
$ ? = $10.00
5.2 + ? = 10
Have $20, spend $11.50 =
Have $20, spend $7.68 =
? = 5
? = 5
? = 20

85. Mental Math # 31 Have $10, spend $8.30 = $1.70
$ $6.01 = $10.00
= 10
Have $20, spend $11.50 = $8.50
Have $20, spend $7.68 = $12.32
= 5
= 5
= 20

86. Mental Math # 32 Have $10, spend $5.15 = Have $10, spend $3.57 =
$ ? = $10.00
3.7 + ? = 10
Have $20, spend $12.75 =
Have $20, spend $9.50 =
? = 1
? = 5
? = 20

87. Mental Math # 32 Have $10, spend $5.15 = $4.85
$ $5.39 = $10.00
= 10
Have $20, spend $12.75 = $7.25
Have $20, spend $9.50 = $10.50
= 1
= 5
= 20

88. Mental Math # 33 20 + 14 = 55 + 43 = 38 + 26 = 65 + 27 = 78 + 135 == = = = =

89. Mental Math # 33
= 34
= 98
= 64
= 92
= 213
= 82
= 72
= 93
= 83
= 306

90. Mental Math # 34 46 + 27 = 35 + 48 = 18 + 73 = 94 + 26 = 82 + 225 == = = = =

91. Mental Math # 34
= 73
= 83
= 91
= 120
= 307
= 96
= 98
= 68
= 133
= 290

92. Mental Math # 35 30 + 25 + 70 = 35 + 40 + 60 + 20 = 50 + 95 + 50 == = = = = = =

93. Mental Math # 35
= 125
= 155
= 195
= 210
= 200
= 150
= 230
= 210
= 300
= 1600

94. Mental Math # 36 = = = = = = = = = =

95. Mental Math # 36
= 150
= 210
= 220
= 210
= 280
= 125
= 230
= 1265
= 430
= 1100

96. Mental Math # 37 29 + 75 = 56 + 52= 25 + 54 = 175 + 24 = 90 + 55 == = = = =

97. Mental Math # 37
= 104
= 108
= 79
= 199
= 145
= 125
= 177
= 202
= 308
= 305

98. Mental Math # 38 28 + 75 = 225 + 76 = 25 + 98 = 198 + 28 = 390 + 38 == = = = =

99. Mental Math # 38
= 103
= 301
= 123
= 226
= 428
= 285
= 308
= 202
= 404
= 208

100. Mental Math # 39 228  2 = 255  5 = 339  3 = 168  4 = 300  50 =
726  6 =
990  90 =
200  5 =
714  7 =
342  3 =

101. Mental Math # 39
228  2 = 114
255  5 = 51
339  3 = 113
168  4 = 42
300  50 = 6
726  6 = 121
990  90 = 11
200  5 = 40
714  7 = 102
342  3 = 114

102. Mental Math # 40 530  5 = 369  3 = 322  2 = 464  4 = 600  30 =
816  8 =
8000  40 =
260  5 =
147  7 =
189  9 =

103. Mental Math # 40
530  5 = 106
369  3 = 123
322  2 = 161
464  4 = 116
600  30 = 20
816  8 = 102
8000  40 = 200
260  5 = 52
147  7 = 21
189  9 = 21

104. Mental Math
Set 2

105. Mental Math # 1 125 + 35 = 2000 + 50 + 400 + 4 = 4.2 + 3 + 0.8 = 23 =
$ $3.85 =
65 + ? = 100
90 x 50 =
135  5 =
100 x =
60 =

106. Mental Math # 1
= 160
= 2454
= 8
23 = 8
$ $3.85 = $6.15
= 100
90 x 50 = 4500
135  5 = 27
100 x 0.15 = 15
60 = 1

107. Mental Math # 2 375 + 45 = 200 + 60 + 140 = 31 = 2.7 + 3 + 1.3 =
You give $5 for a purchase costing $ What is your change?
? = 1000
2800 in scientific notation is =
284  2 =
2.9 x 100 =
37  10 =

108. Mental Math # 2
= 420
= 400
31 = 3
= 7
You give $5 for a purchase costing $ What is your change? $2.45
= 1000
2800 in scientific notation is = 2.8 x 103
284  2 = 142
2.9 x 100 = 290
38.9  10 = 3.89

109. Mental Math # 3 = = =
234.5 in scientific notation =
You give $5 for a purchase costing $ What is your change?
? = 1000
40 x 500 =
396  3 =
5.3 m equals ___ cm =
82.9  10 =

110. Mental Math # 3
= 558
= 2830
= 8
234.5 in scientific notation = x 102
You give $5 for a purchase costing $ What is your change? $1.70
= 1000
40 x 500 =
396  3 = 132
5.3 m equals 530 cm
82.9  10 = 8.29

111. Mental Math # 4 = =
32 = =
$ $6.75 =
? = 100
3000 x 20 =
350  5 =
237  100 =

112. Mental Math # 4
= 6273
= 3850
32 = 9
= 49.8
$ $6.75 = $3.25
= 100
3000 x 20 =
350  5 = 70
237  100 = 2.37
2.304

113. Mental Math # 5 285 + 65 = 4000 + 7 + 500 + 30 = 6.3 + 0.4 + 1.7 == = =
33 =
$ $11.95 =
? + 55 = 200
3 x 700 =
1000  50 =
100 x 0.65 =
636  3

114. Mental Math # 5
= 350
= 4537
= 8.4
33 = 27
$ $11.95 = $8.05
= 200
3 x 700 = 2100
1000  50 = 20
100 x 0.65 = 65
636  3 = 212

115. Mental Math # 6 =
30 = = =
$ $59.00 =
? + 85 = 200
200 x 40 =
1000  20 =
100 x 4.5 =
842  2

116. Mental Math # 6
= 455
30 = 1
= 9.3
= 460
$ $59.00 = $41.00
= 200
200 x 40 = 8000
1000  20 = 50
100 x 4.5 = 450
842  2 = 421

117. Mental Math # 7 =
24 = =
350 =
$ $3.80 =
65 + ? = 300
90 x 30 =
15cm equals __dm =
1000 x 0.15 =
560  5 =

118. Mental Math # 7
= 235
24 = 16
= 8.8
350 = 1
$ $3.80 = $6.20
= 300
90 x 30 = 2700
15cm equals 1.5 dm
1000 x 0.15 = 150
560  5 = 112

119. Mental Math # 8 250 + 125 = 8m equals ___dm 2.3 + 5.8 + 1.7 = 51 =
$ $6.99 =
95 + ? = 300
500 x 70 =
550  5 =
10 x =
361.1  100 =

120. Mental Math # 8 250 + 125 = 375 8m equals 80 dm =
= 9.8
51 = 5
$ $6.99 = $13.01
= 300
500 x 70 =
550  5 = 110
10 x = 13.3
361.1  100 = 3.611

121. Mental Math # 9 8 410 000 in scientific notation = 80 =
$ $ = =
$ $2.10 =
? = 1000
600 x 3 =
446  4 =
2.11 x 1000 =
762.2  100 =

122. Mental Math # 9 8 410 000 in scientific notation = 8.41 x 106 80 = 1
$ $ = $17.80
= 15.3
$ $2.10 = $7.90
= 1000
600 x 3 = 1800
446  4 = 111 R2
2.11 x 1000 = 2110
762.2  100 = 7.622

123. Mental Math # 10 355.5 in scientific notation = 90 km equals ____ m=
1000 – 230 =
$ $9.90 =
180 + ? = 500
500 x 20 =
559  5 =
10 x 27.3 =
590.1  100 =

124. Mental Math # 10 355.5 in scientific notation = 3.555 x 102
90km equals m
= 9.6
1000 – 230 = 770
$ $9.90 = $10.10
= 500
500 x 20 =
559  5 = 111 R4
10 x 27.3 = 273
590.1  100 = 5.901

125. Mental Math # 11 If = 1, then = 530 000 in scientific notation =
7.95m equals ____cm =
1000 – 440 =
You give $10.00 for a purchase costing $ What is your change?
? = 1000
672  6 =
769.1  10 =
3.4 x 102 =

126. Mental Math # 11
If = 1, then = 12.3
in scientific notation = 5.3 x 105
7.95m equals 795cm
= 8.5
1000 – 440 = 560
You give $10.00 for a purchase costing $ What is your change? $3.08
= 1000
672  6 = 112
769.1  10 = 76.91
3.4 x 102 = 340

127. Mental Math # 12 If = 1, then = 385 000 = 5.1 + 5.1 + 7.3 ==
$ $6.75 =
? = 100
3000 x 20 =
350  5 =
4.2 x 1000 =
237  10 =

128. Mental Math # 12 If =1, then = 2.3 385 000 = 3.85 x 105
= 17.5
= 49.8
$ $6.75 = $3.25
= 100
3000 x 20 =
350  5 = 70
4.2 x 1000 = 4200
237  10 = 23.7

129. Mental Math # 13 Two squared added to three squared =
2L equals ___ mL = = =
You give $5 for a purchase costing $ What is your change?
? = 1000
200 x 80 =
384  2 =
2.9 x 100 =
37  10 =

130. Mental Math # 13 Two squared added to three squared = 13
2L equals 2000 mL =
The difference of 52 and 22 =
= 3840
You give $5 for a purchase costing $ What is your change? $2.45
= 1000
200 x 80 =
384  2 = 192
2.9 x 100 = 290
37  10 = 3.7

131. Mental Math # 14 53 dam = ____ m 2 x 103 =
The difference of 52 and 22 = =
You give $5 for a purchase costing $ What is your change?
? = 1000
40 x 500 =
396  3 =
5.3 x 100 =
82  10 =

132. Mental Math # 14
53 dam = 530 m
2 x 103 = 2000
The difference of 52 and 22 = 21
= 8.9
You give $5 for a purchase costing $ What is your change? $1.70
= 1000
40 x 500 =
396  3 = 132
5.3 x 100 = 530
82  10 = 8.2

133. Mental Math # 15 = = = =
You give $10 for a purchase costing $ What is your change?
? = 1000
50 x 60 =
784  7 =
47.3 x 10 =
2444  100

134. Mental Math # 15
= 373
= 6660
= 16.5
= 7.9
You give $10 for a purchase costing $ What is your change? $4.01
= 1000
50 x 60 = 3000
784  7 = 112
47.3 x 10 = 473
2444  100 = 24.44

135. Mental Math # 16 = = =
8.9 – 4.8 =
You give $20 for a purchase costing $1.90 What is your change?
? = 1000
90 x 20 =
575  5 =
0.633 x 100 =
71.4  10

136. Mental Math # 16
= 3743
= 7450
= 19
8.9 – 4.8 = 4.1
You give $20 for a purchase costing $1.90 What is your change? $18.10
= 1000
90 x 20 = 1800
575  5 = 115
0.633 x 100 = 63.3
71.4  10 = 7.14

137. Mental Math # 17 = = =
10.9 – 3.5 =
You give $20 for a purchase costing $4.30 What is your change?
? = 1000
The sum of two cubed and two squared =
726  6 =
11.5 x 100 =
51.37  10 =

138. Mental Math # 17
= 6908
= 3920
=20.2
10.9 – 3.5 = 7.4
You give $20 for a purchase costing $4.30 What is your change? $15.70
= 1000
The sum of two cubed and two squared = 12
726  6 = 121
11.5 x 100 = 1150
51.37  10 = 5.137

139. Mental Math # 18 Which is larger –4 or -7 = 3 + -5 = 100.5 + 20.1 =
8.4 – 3.1 =
You give $100 for a purchase costing $65.00 What is your change?
? = 1000
3100 x 10 =
805  5 =
5.3 x 100 =
1.3  10 =

140. Mental Math # 18 Which is larger –4 or -7 = -4 3 + -5 = -2
= 120.6
8.4 – 3.1 = 5.3
You give $100 for a purchase costing $65.00 What is your change? $35.00
= 1000
3100 x 10 =
805  5 = 161
5.3 x 100 = 530
1.3  10 = 0.13

141. Mental Math # 19 (-5) + (-3) = (+8) + (-2) = (-2) + (-4) =
(-5) + (+10)
You owe you friend $20. You earn $15 babysitting. What is your net worth?
(50) - (-10) =
(-5) + (+3) = =
575  5 = =

142. Mental Math # 19 (-5) + (-3) = -8 (+8) + (-2) = +6 (-2) + (-4) = -6
(-5) + (+10)= +5
You owe you friend $20. You earn $15 babysitting. What is your net worth? $-5
(50) - (-10) = 60
(-5) + (+3) = -2
= +4
575  5 = 115
= -12

143. Mental Math # 20 (-6) + (-3) = (8) + (-2) = (-2) - (-4) =
(5) x (-10) =
You owe you friend $20. You earn $8. What is your net worth?
(50) - (-10) =
(-5) + (+3) =
-20 x -60 =
555  -5 =
2 groups of -10 =

144. Mental Math # 20 (-6) + (-3) = -9 (8) + (-2) = 6 (-2) - (-4) = +2
(5) x (-10) -50
You owe you friend $20. You earn $8. What is your net worth? $-12
(50) - (-10) = 60
(-5) + (+3) = -2
-20 x -60 = 1200
555  -5 = -111
2 groups of -10 = -20

145. Mental Math # 21 (-2) + (+7) = (-8) - (-5) = (-5) - (-10) =
(-6) x (-5) =
You have $50. You earn $20 babysitting. You purchase two tickets for a concert costing $10 each. What is your net worth?
Negative 10 squared =
(+5) + (-3) =
500 x -7 =
-448  -2 =
Yesterday we earn $230 selling cotton candy. Last night we earned $150. Our expenses so far is $20. What is our net profit. =

146. Mental Math # 21 (-2) + (+7) = +5 (-8) - (-5) = -3 (-5) - (-10) = +5
(-6) x (-5) = 30
You have $50. You earn $20 babysitting. You purchase two tickets for a concert costing $10 each. What is your net worth? $50
Negative 10 squared = 100
(+5) + (-3) = +2
500 x -7 = -3500
-448  -2 = 224
Yesterday we earn $230 selling cotton candy. Last night we earned $150. Our expenses so far is $20. What is our net profit. = $360

147. Mental Math # 22 (-12) - (+3) = (-2) - (-5) = (-5) (-10) = 4 + -5 =
You owe $60. You earn $5 an hour babysitting. You baby-sit for 5 hours. What is your net worth?
-23 =
(+5) . (-3) =
-10 x –10 x –10 x -10 =
-4 + ? = -1
-60 = 3

148. Mental Math # 22 (-12) - (+3) = -15 (-2) - (-5) = +3 (-5) (-10) = +50
= -1
You owe $60. You earn $5 an hour babysitting. You baby-sit for 5 hours. What is your net worth? $-35
-23 = -8
(+5) . (-3) = -15
-10 x –10 x –10 x -10 =
= -1
-60 = -20 3

149. Mental Math # 23 3.1 x 102 = (-5) + (+1) = 10.5 + 20.5 + 0.6 =
(+5) + (-4) =
You give $100 for a purchase costing $90.90 What is your change?
7 x x x 1 =
(-3) + (-2) =
729  3 =
52 =
(-3) – (-5) =

150. Mental Math # 23 3.1 x 102 = 310 (-5) + (+1) = -4
= 31.6
(+5) + (-4) = +1
You give $100 for a purchase costing $90.90 What is your change? $9.10
7 x x x 1 = 753
(-3) + (-2) = -5
729  3 = 243
52 = 25
(-3) – (-5) = +2

151. Mental Math # 24 2.3 x 102 = 3 + -2 = 50 = 9 + 40.3 + 0.5 =
$ $6.75 =
in scientific notation =
(-4) + (+4) =
255  5 =
4.2 x 1000 =
23 =

152. Mental Math # 24
2.3 x 102 = 230
= 1
50 = 1
= 49.8
$ $6.75 = $3.25
in scientific notation = 3.45 x 105
(-4) + (+4) = 0
255  5 = 51
4.2 x 1000 = 4200
23 = 8

153. Mental Math # 25 Double 3000 = 3 x 1000 + 5 x 100 = 7.1 + 8.8 + 1.2 =
You spend $5.48. You have $ What is your change?
$ $ =
670 + ? = 1000
542 x 100 =
Three cubed =
844  4 =
81 groups of 102 =

154. Mental Math # 25 Double 3000 = 6000 3 x 1000 + 5 x 100 = 3500
= 17.1
You spend $5.48. You have $ What is your change? $4.52
$ $ = $532.90
= 1000
542 x 100 = 54200
Three cubed = 27
844  4 = 211
81 groups of 102 = 8100

155. Mental Math # 26 Double 2000 and add 300 = 6 x 102 + 3 x 100 ==
You spend $5.70 You have $ What is your change?
Half of 400 minus 10 =
Multiple 9 groups of 50 =
62 x 100 =
Four squared =
784  100 =
3.2 x 103 =

156. Mental Math # 26 Double 2000 and add 300 = 4300
6 x x 100 = 603
= 15.2
You spend $5.70 You have $ What is your change? $4.30
Half of 400 minus 10 = 190
Multiple 9 groups of 50 = 450
62 x 100 = 6200
Four squared = 16
784  100 = 7.84
3.2 x 103 = 3200

157. Mental Math # 27 The complement to a 600 angle =
The supplement to a 1000 angle =
The supplement to a 1600 angle =
The supplement to a 500 angle =
The complement to a 720 angle =
The complement to a 550 angle =
The supplement to a 700 angle =
The supplement to a 400 angle =
The reflex angle to a 700 angle =

158. Mental Math # 27 The complement to a 600 angle = 300
The supplement to a 1000 angle = 800
The supplement to a 1600 angle = 200
The supplement to a 500 angle = 1300
The complement to a 720 angle = 180
The complement to a 550 angle = 350
The supplement to a 700 angle = 1100
The supplement to a 400 angle = 1400
The reflex angle to a 700 angle = 2900

159. Mental Math # 28 The complement to a 750 angle =
The supplement to a 1520 angle =
The supplement to a 1250 angle =
The opposite angle to a 500 angle =
The reflex angle to a 500 angle =
The reflex angle to a 1200 angle =
The measure of angle a =
The measure of angle b =
The measure of angle c = a b c

160. Mental Math # 28 The complement to a 750 angle = 150
The supplement to a 1520 angle = 280
The supplement to a 1250 angle = 550
The opposite angle to a 500 angle = 500
The reflex angle to a 500 angle = 3100
The reflex angle to a 1200 angle = 2400
The measure of angle a = 450
The measure of angle b = 900
The measure of angle c = 450 a b c

161. Mental Math # 29 The m < a = The m < b = The m < c =
The m < d =
The m < e =
The m < f =
The m < g =
The m < h =
The m < i =
The m < j = j a
30o
70o g c b i d h e f

162. Mental Math # 29 The m < a = 1500 The m < b = 300
The m < c = 1500
The m < d = 300
The m < e = 1500
The m < f = 300
The m < g = 700
The m < h = 700
The m < i = 800
The m < j = 1100 j a
30o
70o g c b i d h e f

163. Mental Math # 30 The m < a = The m < b = The m < c =
The m < d =
The m < e =
The m < f =
The m < g =
The m < h =
The m < i =
The m < j = a
120o b c j d h
80o e i f g

164. Mental Math # 30 The m < a = 600 The m < b = 1200
The m < c = 600
The m < d = 1000
The m < e = 1000
The m < f = 800
The m < g = 800
The m < h = 400
The m < i = 400
The m < j = 1400 a
120o b c j d h
80o e i f g

165. Mental Math # 31 3000 + 705 + 20 = 9000 + 20 + 70 = 4.1 + 3.6 + 1.9 =
1000 – 230 =
$ $9.90 =
180 + ? = 500
500 x 20 =
5 x 101 =
10 x 27.3 =
590.1  102 =

166. Mental Math # 31
= 3725
= 9090
= 9.6
1000 – 230 = 770
$ $9.90 = $90.10
= 500
500 x 20 =
5 x 101 = 50
10 x 27.3 = 273
590.1  102 = 5.901

167. Mental Math # 32 Double 650 = 6 x 1000 + 3 x 100 + 2 x 1==
You spend $3.25 You have $ What is your change?
Half of 450 =
Multiple 40 groups of 60 =
6.5 x 100 =
Two squared added to three squared =
6366  3 =
3 groups of 103 =

168. Mental Math # 32 Double 650 = 1300 6 x 1000 + 3 x 100 + 2 x 1 = 6302
= 13.9
You spend $3.25 You have $ What is your change? $6.75
Half of 450 = 225
Multiple 40 groups of 60 = 2400
6.5 x 100 = 650
Two squared added to three squared = 13
6366  3 = 2122
3 groups of 103 = 3000

169. Mental Math # 33 Double the sum of 100 and 150 = 7 x 103 + 8 x 101 ==
You spend $69.90 You have $ What is your change? =
Multiple 100 groups of 3.5 =
The quotient of 35 and 5 =
Two cubed =
900  102 =
8 x 103 =

170. Mental Math # 33 Double the sum of 100 and 150 = 500
7 x x 101 = 7080
= 7.4
You spend $69.90 You have $ What is your change? $30.10 =
Multiple 100 groups of 3.5 = 350
The quotient of 35 and 5 = 7
Two cubed = 8
900  102 = 9
8 x 103 = 8000

171. Mental Math # 34 The difference of 70 and 50 times 2 =
6 x x 100 =
You spend $25.25 You have $ What is your change? =
Multiple 100 groups of 47 =
The quotient of 50 and 10 =
Nine squared =
760  102 =
5 x 103 =

172. Mental Math # 34 The difference of 70 and 50 times 2 = 40
6 x x 100 = 6002
= 29.4
You spend $25.25 You have $100.00
What is your change? $74.75
5) =
6) Multiple 100 groups of 47 = 4700
7) The quotient of 50 and 10 = 5
8) Nine squared = 81
9) 760  102 = 7.6
10) 5 x 103 = 5000

173. Mental Math # 35 The product of 60 and 5 added to 49 = 50 x 102 ==
You spend $79.45 You have $ What is your change? =
Multiple 1000 groups of 2.3 =
The quotient of 555 and 5 =
Six squared, minus ten =
570  100 =
5 x x 101 =

174. Mental Math # 35 The product of 60 and 5 added to 49 = 349
50 x 102 = 5000
= 991
You spend $79.45 You have $ What is your change? $20.55 =
Multiple 1000 groups of 2.3 = 2300
The quotient of 555 and 5 = 111
Six squared, minus ten = 26
570  100 = 570
5 x x 101 = 5090

175. Mental Math # 36 The difference of 400 and 200 multiplied by 4 =
7 x 103 = =
You spend $29.52 You have $ What is your change? =
Multiple 100 groups of 4.53 =
The quotient of 372 and 3 =
four squared, added to twenty =
451  100 =
2 x x 101 =

176. Mental Math # 36 The difference of 400 and 200 multiplied by 4 = 800
7 x 103 = 7000
= 1042
You spend $29.52 You have $ What is your change? $70.48 =
Multiple 100 groups of 4.53 = 453
The quotient of 372 and 3 = 124
four squared, added to twenty = 36
451  100 = 451
2 x x 101 = 290

177. Mental Math # 37 Double 320 = 6 x 1000 + 3 x 100 + 2 x 1==
You spend $3.89 You have $ What is your change?
Half of 660 =
Multiple 300 groups of 6 =
6.5 x 100 =
Two squared added to ten squared =
6339  3 =
6 groups of 103 =

178. Mental Math # 37 Double 320 = 640 6 x 1000 + 3 x 100 + 2 x 1= 6302
= 10.7
You spend $3.89 You have $ What is your change? $6.11
Half of 660 = 330
Multiple 300 groups of 6 = 1800
6.5 x 100 = 650
Two squared added to ten squared = 104
6339  3 = 2113
6 groups of 103 = 6000

179. Mental Math # 38 Double 700 = 63 000 in scientific notation ==
You spend $5.65 You have $ What is your change?
Half of 2010 =
Multiple 5 groups of 700 =
0.56 x 100 =
The difference of ten squared and five squared =
575  5 =
2 groups of 103 =

180. Mental Math # 38
Double 700 = 1400
in scientific notation = 6.3 x 104
= 301.5
You spend $5.65 You have $ What is your change? 4.35
Half of 2010 = 1005
Multiple 5 groups of 700 = 3500
0.56 x 100 = 56
The difference of ten squared and five squared = 75
575  5 = 115
2 groups of 103 = 2000

181. Mental Math # 39 Double 2000 added to 342 =
in scientific notation =
100.3 x 2 =
You spend $50.90 You have $ What is your change?
Half of 612 =
Multiple 200 groups of 70 =
6.27 x 100 =
The sum of ten squared and five squared =
715  5 =
8 groups of 102 =

182. Mental Math # 39 Double 2000 added to 342 = 4342
in scientific notation = 7.8 x 105
100.3 x 2 = 200.6
You spend $50.90 You have $ What is your change? $49.10
Half of 612 = 306
Multiple 200 groups of 70 =
6.27 x 100 = 627
The sum of ten squared and five squared = 125
715  5 = 143
8 groups of 102 = 800

183. Mental Math # 40
The difference between three groups of five hundred and two hundred =
in scientific notation =
200.2 x 3 =
You spend $65.00 You have four $20.00 bills. What is your change? $
Half of 866 =
Multiple 20 groups of 150 =
6.27 x 100 =
The sum of two squared and three squared =
655  5 =
8.1 x 102 =

184. Mental Math # 40
The difference between three groups of five hundred and two hundred = 1300
in scientific notation = x 103
200.2 x 3 = 600.6
You spend $65.00 You have four $20.00 bills. What is your change? $15.00
Half of 866 = 433
Multiple 20 groups of 150 = 3000
6.27 x 100 = 627
Sum of two squared and three squared = 13
655  5 = 131
8.1 x 102 = 810

185. Mental Math
Set 3

186. Mental Math # 1
The difference between five groups of one hundred and fifty =
in scientific notation =
400.5 x 2 =
You spend $71.00 You have two $50 bills. What is your change?
Half of 1040 =
Multiple 30 groups of 70 =
97 x 1000 =
Sum of ten cubed and five squared =
723  3 =
52 x 103 =

187. Mental Math # 1
The difference between five groups of one hundred and fifty = 450
in scientific notation = 7.35 x 105
400.5 x 2 = 801
You spend $71.00 You have two $50 bills. What is your change? $29.00
Half of 1040 = 520
Multiple 30 groups of 70 = 2100
97 x 1000 =
Sum of ten cubed and five squared = 1025
723  3 = 241
52 x 103 =

188. Mental Math # 2
Three groups of one hundred increased by two hundred forty two =
in scientific notation = =
You spend $36.05 You have two $20 bills. What is your change?
Half of 584 =
Multiple 35 groups of 200 =
3.4 x 100 =
Sum of ten squared and four squared = =
79 x 102 =

189. Mental Math # 2
Three groups of one hundred increased by two hundred forty two = 542
in scientific notation = x 102 =
You spend $36.05 You have two $20 bills. What is your change? $3.95
Half of 584 = 292
Multiple 35 groups of 200 = 7000
3.4 x 100 = 340
Sum of ten squared and four squared = 116
= -9
79 x 102 = 7900

190. Mental Math # 3 Three groups of two hundred decreased by one hundred =
in scientific notation = =
You spend $24.50 You have a $50 bill. What is your change?
Half of 876 =
Multiple 3 groups of 500 =
45 x 1000 =
Sum of three squared and five squared = =
9 x 103 =

191. Mental Math # 3
Three groups of two hundred decreased by one hundred = 500
in scientific notation = 4.7 x 104
= 70.32
You spend $24.50 You have a $50 bill. What is your change? $25.50
Half of 876 = 438
Multiple 3 groups of 500 = 1500
45 x 1000 =
Sum of three squared and five squared = 34
= -2
9 x 103 = 9000

192. Mental Math # 4 Four groups of twenty decreased by one group of ten =
27O 000 in scientific notation = =
You spend $45.00 You have three $20 bills. What is your change?
Half of 706 =
Multiple 3 groups of 800 =
5 x x 100 =
Sum of three squared and ten squared =
(-5) – (-7) =
5 x 103 =

193. Mental Math # 4
Four groups of twenty decreased by one group of ten = 70
27O 000 in scientific notation = 2.7 x 105
= 14.5
You spend $45.00 You have three $20 bills. What is your change? $15.00
Half of 706 = 353
Multiple 3 groups of 800 = 2400
5 x x 100 = 5300
Sum of three squared and ten squared = 109
(-5) – (-7) = +2
5 x 103 = 5000

194. Mental Math # 5
Four groups of fifty decreased by one group of twenty =
in scientific notation = =
You spend $69.00 You have four $20 bills. What is your change?
Half of 524 =
5 groups of 500 =
3 x x x 1 =
Sum of five squared and ten squared =
590 + ? = 1000
6 x 103 =

195. Mental Math # 5
Four groups of fifty decreased by one group of twenty = 180
in scientific notation = 9.4 x 104
= 13.9
You spend $69.00 You have four $20 bills. What is your change? $11.00
Half of 524 = 262
5 groups of 500 = 2500
3 x x x 1 = 3705
Sum of five squared and ten squared = 125
= 1000
6 x 103 = 6000

196. Mental Math # 6
Eight groups of one hundred decreased by three hundred fifty =
in scientific notation = =
You spend $57.35 You have six $10 bills. What is your change?
Half of 966 =
40 groups of 50 =
3 x x x 10 =
Sum of two cubed and four squared =
270 + ? = 1000
4 x 101 =

197. Mental Math # 6
Eight groups of one hundred decreased by three hundred fifty = 450
in scientific notation = 8.91 x 107
= 16.5
You spend $57.35 You have six $10 bills. What is your change? $2.65
Half of 966 = 483
40 groups of 50 = 2000
3 x x x 10 = 9350
Sum of two cubed and four squared = 24
= 1000
4 x 101 = 40

198. Mental Math # 7
Three groups of two hundred increased by three groups of fifty =
in scientific notation = =
You spend $32.50 You have two $20 bills. What is your change?
972  3 =
30 groups of 500 =
(+3) + (-5) =
Sum of three cubed and ten squared =
I owe seven dollars to my friend. I get my allowance of ten dollars. What is my net worth? =
78 x 100 =

199. Mental Math # 7
Three groups of two hundred increased by three groups of fifty = 750
in scientific notation = 5.55 x 106
= 11
You spend $32.50 You have two $20 bills. What is your change? $7.50
972  3 = 324
30 groups of 500 =
(+3) + (-5) = -2
Sum of three cubed and ten squared = 127
I owe seven dollars to my friend. I get my allowance of ten dollars. What is my net worth? = +3
78 x 100 = 78

200. Mental Math # 8 Double 150 added to 198 =
341.5 in scientific notation =
123 x 3 =
You spend $40.20 You have five $ What is your change?
Half of 276 =
Multiple 90 groups of 90 =
(-5) - (-8) =
Two to the exponent four =
6/30 in lowest terms is =
7 groups of 100 =

201. Mental Math # 8 Double 150 added to 198 = 498
341.5 in scientific notation = x 102
123 x 3 = 369
You spend $40.20 You have five $ What is your change? $9.80
Half of 276 = 138
Multiple 90 groups of 90 = 8100
(-5) - (-8) = +3
Two to the exponent four = 16
6/30 in lowest terms is = 1/5
7 groups of 100 = 7

202. Mental Math # 9 Double 551 = 40 500 in scientific notation = 312 x 3 =
You spend $73.90 You have four $ What is your change?
Half of 724 =
Multiple 40 groups of 600 =
(5) - (-4) =
Two to the exponent five plus five =
4/12 in lowest terms is =
12/5 as a mixed number =

203. Mental Math # 9
Double 551 = 1102
in scientific notation = 4.05 x 104
312 x 3 = 936
You spend $73.90 You have four $ What is your change? $6.10
Half of 724 = 362
Multiple 40 groups of 600 =
(5) - (-4) = +9
Two to the exponent five plus five = 37
4/12 in lowest terms is = 1/3
12/5 as a mixed number = 2 2/5

204. Mental Math # 10 Double 623 = 800 000 in scientific notation =
211 x 5 =
You spend $53.50 You have three $ What is your change?
Half of 872 =
Multiple 60 groups of 600 =
(1) + (-4) =
Five to the exponent two plus ten =
3/15 in lowest terms is =
14/3 as a mixed number =

205. Mental Math # 10
Double 623 = 1246
in scientific notation = 8 x 105
211 x 5 = 1055
You spend $53.50 You have three $ What is your change? $6.50
Half of 872 = 436
Multiple 60 groups of 600 =
(1) + (-4) = -3
Five to the exponent two plus ten = 35
3/15 in lowest terms is = 1/5
14/3 as a mixed number = 4 2/3

206. Mental Math # 11 Which is larger 2/11 or 2/9 =
12/18 in lowest terms =
18/4 as a mixed number =
3/10 as a percent =
2/25 as a percent =
0.05 as a percent =
131/100 as a decimal =
9/10 of a bars added to 5/8 of a bar is closer to 1, 1 1/2 or 2 whole bars =

207. Mental Math # 11 Which is larger 2/11 or 2/9 = 2/9
12/18 in lowest terms 2/3
18/4 as a mixed number = 4 1/2
3/10 as a percent = 30 %
2/25 as a percent = 8%
0.05 as a percent = 5 %
131/100 as a decimal = 1.31
9/10 of a bars added to 5/8 of a bar is closer to 1, 1 1/2 or 2 whole bars = 1 1/2

208. Mental Math # 12 Which is larger 5/9 or 3/8 =
6/15 in lowest terms
15/3 as a mixed number =
9/10 as a percent =
11/20 as a percent =
0.18 as a percent =
235/100 as a decimal =
5/12 of a bars added to 11/20 of a bar is closer to 1, 1 1/2 or 2 whole bars =

209. Mental Math # 12 Which is larger 5/9 or 3/8 = 5/9
6/15 in lowest terms 2/5
15/3 as a mixed number = 5
9/10 as a percent = 90 %
11/20 as a percent = 55%
0.18 as a percent = 18%
235/100 as a decimal = 2.35
5/12 of a bars added to 11/20 of a bar is closer to 1, 1 1/2 or 2 whole bars = 1

210. Mental Math # 13 Which is larger 11/20 or 7/18 =
16/20 in lowest terms =
7/2 as a mixed number =
1/5 of 20 =
5/25 as a percent =
0.07 as a percent =
34/100 as a decimal =
11/ /20 of a bar is closer to 1,
1 1/2 or 2 whole bars =

211. Mental Math # 13 Which is larger 11/20 or 7/18 = 11/20
16/20 in lowest terms = 4/5
7/2 as a mixed number = 3 1/2
1/5 of 20 = 4
5/25 as a percent = 20%
0.07 as a percent = 7%
34/100 as a decimal = 0.34
11/ /20 of a bar is closer to 1,
1 1/2 or 2 whole bars = 1 1/2

212. Mental Math # 14
The diagram best represents what percent shaded? 30%, 50% or 70%

213. 3) The diagram best represents what percent shaded? 30%, 50% or 70%

214. 5) The diagram best represents what percent shaded? 38%, 50% or 66%

215. 7) The diagram best represents what percent shaded? 30%, 50% or 70%

216. 9) The diagram best represents what percent shaded? 25%, 50% or 75%

217. Mental Math # 14
The diagram best represents what percent shaded? 30%, 50% or 70%

218. 3) The diagram best represents what percent shaded? 30%, 50% or 70%

219. 5) The diagram best represents what percent shaded? 38%, 50% or 66%

220. 7) The diagram best represents what percent shaded? 30%, 50% or 70%

221. 9) The diagram best represents what percent shaded? 25%, 50% or 75%

222. Mental Math # 15 Double the sum of 100 and 150 = 7 x 103 + 8 x 101 ==
You spend $69.90 You have $ What is your change? =
Multiple 100 groups of 3.5 =
The quotient of 35 and 5 =
Two cubed =
900  102 =
8 x 103 =

223. Mental Math # 15 Double the sum of 100 and 150 = 500
7 x x 101 = 7080
= -8
You spend $69.90 You have $ What is your change? $30.10 =
Multiple 100 groups of 3.5 = 350
The quotient of 35 and 5 = 7
Two cubed = 8
900  102 = 9
8 x 103 = 8000

224. Mental Math # 16 The difference of 70 and 50 times 2 =
6 x x 100 = =
You spend $25.25 You have $100.00
What is your change?
5) =
6) Multiple 100 groups of 47 =
7) The quotient of 50 and 10 =
8) Nine squared =
9) 760  102 =
10) 5 x 103 =

225. Mental Math # 16 The difference of 70 and 50 times 2 = 40
6 x x 100 = 6002
= 29.4
You spend $25.25 You have $100.00
What is your change? $74.75
5) =
6) Multiple 100 groups of 47 = 4700
7) The quotient of 50 and 10 = 5
8) Nine squared = 81
9) 760  102 = 7.6
10) 5 x 103 = 5000

226. Mental Math # 17 Double 2000 added to 342 =
in scientific notation =
100.3 x 2 =
You spend $50.90 You have $ What is your change?
Half of 612 =
Multiple 200 groups of 70 =
$6.27 x 100 =
The sum of ten squared and five squared =
715  5 =
8 groups of 102 =

227. Mental Math # 17 Double 2000 added to 342 = 4342
in scientific notation = 7.8 x 105
100.3 x 2 = 200.6
You spend $50.90 You have $ What is your change? $49.10
Half of 612 = 306
Multiple 200 groups of 70 =
$6.27 x 100 = $627
The sum of ten squared and five squared = 125
715  5 = 143
8 groups of 102 = 800

228. Mental Math # 18 2 x 8 x 5 = 25 x 22 x 4 = 2 x 9 x 50 = 4 x 6 x 5 =

229. Mental Math # 18 2 x 8 x 5 = 80 25 x 22 x 4 = 2200 2 x 9 x 50 = 900

230. Mental Math # 19 4 x 52 x 25 = 3 x 4 x 5 x 6 = 2 x 3 x 50 =

231. Mental Math # 19
4 x 52 x 25 = 5200
3 x 4 x 5 x 6 = 360
2 x 3 x 50 = 300
2 x 6 x 500 = 6000
10 x 40 x 2 = 800
20 x 5 x 7 x 2 = 1400
2 x 9 x 5 x 2 = 180
2 x 4 x 25 x 11 = 2200
2 x 2 x 5 x 20 = 400
2 x 9 x 4 x 5 x 0 = 0

232. Mental Math # 20 6 x 15 x 2 = 3 x 5 x 5 x 2 = 4 x 5 x 25 x 4 =

233. Mental Math # 20
6 x 15 x 2 = 180
3 x 5 x 5 x 2 = 150
4 x 5 x 25 x 4 = 2000
50 x 6 x 2 x 6 = 3600
50 x 4 x 12 = 2400
2 x 5 x 7 x 2 = 140
20 x 13 x 5 = 1300
4 x 25 x 56 = 5600
9 x 2 x 50 x 9 = 8100
2 x 6 x 4 x 5 = 240