**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 1
- Mental Maths for Class 2
- Mental Maths for Class 3
- Mental Maths for Class 4
- Mental Maths for Class 5
- Mental Maths for Class 6
- Mental Maths for Class 7
- Mental Maths for Class 8

**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. 1^{2} +
2^{2}

d. 4
× 4 × 4

**29.**
Which of the following is an even number?

a. 5^{4} b. 3^{6}

c. 2^{5} d.
1^{8}

**30.**
How is 4^{6} 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. 3^{3} × 5^{5}

b. 3^{4} × 5^{2}

c. 2^{5} × 5^{2}

d. 5^{4} × 3^{4}

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

a. –2^{3} b. 2^{3}

c. 1/2^{3} 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 8*x *to get 13*x*?

**36.** The perimeter of a triangle is 4*x *+ 7 units and two of its
sides are 2*x *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, (8*x *+ 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 8*x *+ 3 = 35, find the value of 4*x*.

**67.** Solve: –5*x *+ 7 = 5*x *–13

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

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

**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 cm^{2}.

**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**