Mental Maths for Class 7

Mental Maths for Class 7

Mental Maths for Class 7

Mental Maths for class 7 covers all types of mental maths questions for class 7 students.

Mental Maths for Class 7 covers the following topics:

•       Integers
•       Fractions
•       Decimals
•       Rational Numbers
•       Powers and Exponents
•       Algebraic Expressions
•       Lines and Angles
•       Properties of Triangles
•       Symmetry
•       Data Handling
•       Linear Equations
•       Ratio and Proportion
•       Percentage and its Applications
•       Visualising Solid Shapes
•       Congruence of Triangles
•       Perimeter and Area
•       Probability

Mental Maths for Class 7 with Answers

1. Evaluate: –6 – 4 + 3 = _________

2.  Simplify: 12 – 6 + 6 ÷ 2 – (–13 + 7)

3. Find the smallest integer among the given integers. Which two integers give the smallest possible sum?

0, –3, –5, –7, –10, –11

4. Fill in the blanks.

a. (–24) + _______ = 99

b. (–35) – _______ = –51

c. 500 + _______ = –500

d. 191 + _______ = 190

5. Find the value of (–3) × 4 × (–6).

6. Find the integer whose product with (–1) is 300.

7. Arrange the following in ascending order.

(–100) ÷ 100; (–1000) ÷ 10; (–10) ÷ (–100); 100 ÷ (–10)

8. An emperor was born in 58 BC and died in 12 AD. How many years did he live?

9. Simplify: 70 – [6 + 3 of (32 – 3 × 9)]

10. What should be added to –3/4 to get the result as 1?

11. Find 4/50 of a kilogram in grams.

12. Find 7/12 of a day in hours.

13. What fraction is 180 grams of 3 kg?

14. Each cow in a herd gives one-third of the total milk each day. How many cows are there in the herd?

15. Priya bought a cake that weighed 4/5 kg. She cut it into pieces of 1/10 kg each. How many pieces did she get?

16. Neha took 2.54 minutes to complete a race and Reena took 2.504 minutes to complete the race. Who won the race?

17. Find x, if 856.92 – x = 679.80

18. Evaluate: 0.55 – 0.0055

19. Add: 2 + 7 + 20.4 + 39.975

20. Find the sum of 0.6, 0.06 and 0.006.

Choose the correct option. (Q21 – Q32)

21. 0.4 × 0.5 = ______________.

a. 2              b. 200

c. 0.2           d. 0.02

22. If 1.225 × 1.55 = 1.89875, then which of the following numbers would 122.5 × 15.5 be closest to?

a. 204          b. 2044

c. 2045        d. 20440

23. 6.45 × ______________ = 6450

a. 1             b. 10

c. 100         d. 1000

24. How many decimal places will be there in the product of 3.4 and 25 tenth?

a. 0        b. 1

c. 2        d. 3

25. 10.09 × 1000 = ______________

a. 1009           b. 0.1009

c. 10090         d. 10009

26. 0.05 ÷ 0.5 = _______________

a. 0.01           b. 0.11

c. 0.1             d. 0.001

27. (–5)3 is the same as ________________________.

a. (–5)3 –5

b. –(3 × 3 × 3 × 3 × 3)

c. (–5) × (–5 ) × (–5)

d. (–5 ) + (–5) + (–5)

28. Which of the following can be expressed as a power of 3?

a. 3 + 3 + 3 + 3

b. 3 × 3 × 3 × 3

c. 12 + 22

d. 4 × 4 × 4

29. Which of the following is an even number?

a. 54              b. 36

c. 25              d. 18

30. How is 46 written in the expanded form?

a. 6 × 4

b. 6 × 6 × 6 × 6

c. 4 + 6

d. 4 × 4 × 4 × 4 × 4 × 4

31. Express 2025 as the product of its prime factors.

a. 33 × 55

b. 34 × 52

c. 25 × 52

d. 54 × 34

32. Which of the following has an exponent with a negative index?

a. –23             b. 23

c. 1/23            d. –3

33. Express (27)–2 as a power with base 3.

34. Which is the greater of the two numbers:

0.000000026 or 2.6 × 10–8

35. What must be added to 8x to get 13x?

36. The perimeter of a triangle is 4x + 7 units and two of its sides are 2x units and x units. Find the third side of the triangle.

37. Add: pq qr, qr rp, rp pq

38. Evaluate:

a. 10 + y – 2, when y = 6

b. 3(b – 5) + 7, when b = 10

39. Two supplementary angles are in the ratio 5 : 4. Find the angles.

40. Two complementary angles are in the ratio 2 : 3. Find the angles.

41. If two interior angles on the same side of a transversal intersecting two parallel lines are in ratio 2 : 3, then what is the smaller angle?

42. Two angles, (8x + 36) °and 156°are vertically opposite. Find the value of 'x'.

43. If two angles of a triangle are 32° and 66°, find the measure of the third angle.

44. One of the angles of a triangle is 96° and the other two angles are equal. Find the measures of the other two angles.

45. The three angles of a triangle are in the ratio 1 : 2 : 1. Find the angles of the triangle.

46. One of the equal angles of an isosceles triangle is 30°. Find the measure of its third angle.

47. Can there be rotational symmetry of order more than 1, if the angle of rotation is 16°?

48. What is the order of rotational symmetry of a ceiling fan with three blades?

49. What is the order of rotational symmetry of the letter B and the letter H?

50. A shape has rotational symmetry of order 5. What is the angle of rotation?

51. The angle of rotational symmetry for a shape is 60°. What is the order of rotational symmetry?

52. Find the arithmetic mean of integers from –5 to 5.

53. Find the mean of the observations: 4, 5, 11, 19, 21, 24.

54. Find the median of the factors of 36.

55. The mean of 5, 6, 10, 14, 20, x, 18, 12 is 12. Find x.

56. The mean of 12 numbers is 30. If 3 is added to each number, what is the new mean?

57. The mean of 8 numbers is 20. If 4 is subtracted from each number, what is the new mean?

58. What is the sum of 12 numbers, whose mean is 50?

59. Find the mode of the given data.

12, 9, 5, 9, 1, 6, 9, 11, 7, 10, 7, 8

60. Find the mode of the given data.

36, 42, 39, 36, 45, 52, 34, 36, 45

61. The data given below is in ascending order. The median of the data is 25. Find the value of x.

15, x, 22, x + 7, 34, 37, 40

62. What is the sum of 2 and additive inverse of 5/4?

63. Express 32/–24 in its standard form.

64. Express 2.25 as a rational number and find its multiplicative inverse.

65. Express 1/7 as a decimal and name the type of decimal it is.

66. If 8x + 3 = 35, find the value of 4x.

67. Solve: –5x + 7 = 5x –13

68. Write an equation for the given statement. One-third of a number is 10 less than itself.

69. Solve: 3(4x + 5) = 5(2x + 7)

70. 4 added to six times a number gives 58. Find the number.

71. When a number is multiplied by 3, its value increases by 20. What is the number?

72. The sum of three consecutive numbers is 72. Find the numbers.

73. If x : y = 1 : 2, find the value of 5x : 3y.

74. Find the ratio of 400 mL to 2 L.

75. AB is a line segment of length 24 cm. P is a point on AB which divides AB in the ratio 5 : 7. Find the lengths of AP and PB.

76. Find x if 2 : 3 = 3 : x.

77. Find the fourth proportional to 15, 20 and 21.

78. If a : b = 4 : 5 and b : c = 10 : 7, find a : c.

79. A motor bike can go 480 km with 12 litres of petrol. How far can it go with 20 litres of petrol?

80. If 12 men can weave 96 metres of cloth in a day, how many metres of cloth can be woven by 5 men in a day?

81. Convert the ratio 5 : 4 to percentage.

82. If one-fourth of a figure is shaded, what is the percentage of the unshaded portion?

83. If the cost price of an item is ₹1250 and the selling price is ₹1375, find the profit percent.

84. Rony makes 20% profit by selling a jug for ₹240. At what price had Rony purchased the jug?

85. If the amount repaid is ₹360 and the principal is ₹342, find the interest.

86. At what rate per cent per annum will ₹250 amount to ₹300 in 5 years?

87. Find the simple interest at the rate of 4% p.a. for 2 years on ₹1500.

Choose the correct answer (Q88  Q91).

88. The lateral faces of a pyramid have the shape of ______________.

a. squares       b. triangles

c. rectangles   d. trapeziums

89. Each lateral face of a prism has the shape of a ______________.

a. square        b. triangle

c. rectangle    d. trapezium

90. The number of vertices and number of edges in a pentagonal prism are ______________.

a. 5, 10       b. 10, 12

c. 7, 10       d. 10, 15

91. Which of the following solid(s) has six faces?

a. square prism

b. cube

c. pentagonal pyramid

d. all of these

Fill in the blanks (Q92  Q94).

92. A triangular prism has _______ faces and _______ edges.

93. A cuboid has _______ edges and _______ vertices.

94. A square-based pyramid has _______ edges and _______ faces.

95. ABC and PQR are two triangles such that AB = QR, AC = PR and B = R. Are the triangles congruent?

96. The perimeter of a square field is 240 cm. Find the area of the square field.

97. How many squares of side 4 cm cover the surface of a rectangle with dimensions 16 m by 10 cm?

98. The base of a parallelogram is equal to its height. If the area of the parallelogram is 225 cm2, find the base of the parallelogram.

99. Find the height of a triangle whose base is 20 cm and area is 600 cm2.

100. Fin the area of a circle of radius 2.1 cm.

101. Find the circumference of a circle whose diameter is 4.2 cm.

102. The circumference of a circular field is 176 cm. Find the area of the field.

103. A circular disc covers an area of 154 sq. cm. What is the circumference of the disc?

104. A die is tossed once. Find the probability of getting a square number on the top face.

105. There are 4 blue marbles and 5 yellow marbles in a jar. What is the probability of getting a yellow marble?

106. A jar contains 6 red marbles, 7 green marbles and 4 white marbles. What is the probability of taking out a marble which is not red?

107. A die is tossed at random. What is the probability of getting a multiple of 5?

108. If a card is drawn from the deck of 52 cards, find the probability of getting a black card.

Mental Maths for Class 7 Answer Keys

1. -7               2. 15

3. -11; -10 and -11

4. a. 123         b. 16

c. -1000           d. -1

5. 72                6. -300

7. (–1000) ÷ 10; 100 ÷ (–10); (–100) ÷ 100; (–10) ÷ (–100)

8. 70 years              9. 49

10. 7/4                11. 80 grams

12. 14 hours       13. 3/50

14. 3 cows         15. 8 pieces

16. Reena           17. x = 177.12

18. 0.5445       19. 69.375

20. 0.666         21. c

22. b                23. d

24. a                25. c

26. c                 27. c

28. b                 29. c

30. d                 31. b

32. c                 33. 3-6

34. Both are equal

35. 5x

36. (x + 7) units

37. 0

38. a. 14              b. 22

39. 100°, 80°      40. 36°, 54°

41. 72°             42. x = 15°

43. 82°            44. 42°, 42°

45. 45°, 90°, 45°

46. 120°         47. Yes

48. 3

49. Order of rotational symmetry of B = 1;

Order of rotational symmetry of H = 2

50. 72°           51. 6

52. 0              53. 14

54. 6              55. x = 11

56. 33            57. 16

58. 600          59. 9

60. 36           61. 18

62. ¾           63. -4/3

64. 9/4; 4/9

65. 0.142857142……; Non-terminating repeating decimal

66. 16         67. x = 2

68. x/3 = x – 10

69. x = 10

70. 9                71. 10

72. 23, 24, 25

73. 5 : 6           74. 1 : 5

75. 10 cm and 14 cm

76. 4.5              77. 28

78. 8 : 7

79. 800 km

80. 40 metres

81. 125%            82. 75%

83. 10%              84. Rs 200

85. Rs 18            86. 4%

87. Rs 120         88. a. b

89. c                  90. d

91. d                 92. 5; 9

93. 12; 8          94. 8; 5

95. No

96. 3600 sq. cm

97. 1000 squares

98. 15 cm       99. 60 cm

100. 13.86 sq. cm

101. 26.4 cm

102. 2464 sq. cm

103. 44 cm

104. 1/3         105. 5/9

106. 11/17

107. 1/6             108. ½

Worksheets for Maths

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Maths Worksheets for Class 2

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Maths Worksheets for Class 7

Maths Worksheets for Class 8

Maths Worksheets for Class 9