NCERT Exemplar Solutions
Class 7 - Mathematics
Unit 8: Rational Numbers

Complete NCERT Exemplar Solutions for Class 7 - Unit 8: Rational Numbers with answers and step by step solutions.

Multiple Choice Questions

In each of the following questions 1 to 12, there are four options, out of which, only one is correct. Write the correct one.

Question.  1

1. A rational number is defined as a number that can be expressed in the form \( \dfrac{p}{q} \), where \(p\) and \(q\) are integers and

(a)

(a) \(q = 0\)

(b)

(b) \(q = 1\)

(c)

(c) \(q \neq 1\)

(d)

(d) \(q \neq 0\)

Open

Question.  2

Which of the following rational numbers is positive?

(a)

(a) \(-\dfrac{8}{7}\)

(b)

(b) \(\dfrac{19}{-13}\)

(c)

(c) \(\dfrac{-3}{-4}\)

(d)

(d) \(\dfrac{-21}{13}\)

Open

Question.  3

Which of the following rational numbers is negative?

(a)

(a) \(-\dfrac{3}{7}\)

(b)

(b) \(\dfrac{-5}{-8}\)

(c)

(c) \(\dfrac{9}{8}\)

(d)

(d) \(\dfrac{3}{-7}\)

Open

Question.  4

In the standard form of a rational number, the common factor of numerator and denominator is always:

(a)

(a) 0

(b)

(b) 1

(c)

(c) -2

(d)

(d) 2

Open

Question.  5

Which of the following rational numbers is equal to its reciprocal?

(a)

(a) 1

(b)

(b) 2

(c)

(c) \(\dfrac{1}{2}\)

(d)

(d) 0

Open

Question.  6

The reciprocal of \(\dfrac{1}{2}\) is

(a)

(a) 3

(b)

(b) 2

(c)

(c) -1

(d)

(d) 0

Open

Question.  7

The standard form of \(-\dfrac{48}{60}\) is

(a)

(a) \(\dfrac{48}{60}\)

(b)

(b) \(\dfrac{-60}{48}\)

(c)

(c) \(-\dfrac{4}{5}\)

(d)

(d) \(\dfrac{-4}{-5}\)

Open

Question.  8

Which of the following is equivalent to \(\dfrac{4}{5}\)?

(a)

(a) \(\dfrac{5}{4}\)

(b)

(b) \(\dfrac{16}{25}\)

(c)

(c) \(\dfrac{16}{20}\)

(d)

(d) \(\dfrac{15}{25}\)

Open

Question.  9

How many rational numbers are there between two rational numbers?

(a)

(a) 1

(b)

(b) 0

(c)

(c) unlimited

(d)

(d) 100

Open

Question.  10

In the standard form of a rational number, the denominator is always a

(a)

(a) 0

(b)

(b) negative integer

(c)

(c) positive integer

(d)

(d) 1

Open

Question.  11

To reduce a rational number to its standard form, we divide its numerator and denominator by their

(a)

(a) LCM

(b)

(b) HCF

(c)

(c) product

(d)

(d) multiple

Open

Question.  12

Which is greater number in the following:

(a)

(a) \(-\dfrac{1}{2}\)

(b)

(b) 0

(c)

(c) \(\dfrac{1}{2}\)

(d)

(d) -2

Open

Fill in the Blanks

In Questions 13 to 46, fill in the blanks to make the statements true.

Question. 13

\(-\dfrac{3}{8}\) is a _____ rational number.

Answer:

\(-\dfrac{3}{8}\) is a negative rational number.

Open

Question. 14

1 is a _____ rational number.

Answer:

1 is a positive rational number.

Open

Question. 15

The standard form of \(-\dfrac{8}{-36}\) is _____.

Answer:

The standard form of \(-\dfrac{8}{-36}\) is \(\dfrac{2}{7}\).

Open

Question. 16

The standard form of \(\dfrac{18}{-24}\) is _____.

Answer:

The standard form of \(\dfrac{18}{-24}\) is \(-\dfrac{3}{4}\).

Open

Question. 17

On a number line, \(-\dfrac{1}{2}\) is to the _____ of zero (0).

Answer:

On a number line, \(-\dfrac{1}{2}\) is to the left of zero (0).

Open

Question. 18

On a number line, \(\dfrac{4}{3}\) is to the _____ of zero (0).

Answer:

On a number line, \(\dfrac{4}{3}\) is to the right of zero (0).

Open

Question. 19

\(-\dfrac{1}{2}\) is _____ than \(\dfrac{1}{5}\).

Answer:

\(-\dfrac{1}{2}\) is smaller than \(\dfrac{1}{5}\).

Open

Question. 20

\(-\dfrac{3}{5}\) is _____ than 0.

Answer:

\(-\dfrac{3}{5}\) is smaller than 0.

Open

Question. 21

\(-\dfrac{16}{24}\) and \(\dfrac{20}{-16}\) represent _____ rational numbers.

Answer:

\(-\dfrac{16}{24}\) and \(\dfrac{20}{-16}\) represent different rational numbers.

Open

Question. 22

\(-\dfrac{27}{45}\) and \(-\dfrac{3}{5}\) represent _____ rational numbers.

Answer:

\(-\dfrac{27}{45}\) and \(-\dfrac{3}{5}\) represent same rational numbers.

Open

Question. 23

Additive inverse of \(\dfrac{2}{3}\) is _____.

Answer:

Additive inverse of \(\dfrac{2}{3}\) is -\dfrac{2}{3}.

Open

Question. 24

\(-\dfrac{3}{5} + \dfrac{2}{5} = \) _____.

Answer:

\(-\dfrac{3}{5} + \dfrac{2}{5} = -\dfrac{1}{5}\).

Open

Question. 25

\(-\dfrac{5}{6} + -\dfrac{1}{6} = \) _____.

Answer:

\(-\dfrac{5}{6} + -\dfrac{1}{6} = -1\).

Open

Question. 26

\(\dfrac{3}{4} \times ( -\dfrac{2}{3} ) = \) _____.

Answer:

\(\dfrac{3}{4} \times ( -\dfrac{2}{3} ) = -\dfrac{1}{2}\).

Open

Question. 27

\(-\dfrac{5}{3} \times ( -\dfrac{3}{5} ) = \) _____.

Answer:

\(-\dfrac{5}{3} \times ( -\dfrac{3}{5} ) = 1\).

Open

Question. 28

\(-\dfrac{6}{7} = \dfrac{__}{42}\)

Answer:

\(-\dfrac{6}{7} = \dfrac{-36}{42}\)

Open

Question. 29

\(\dfrac{1}{2} = \dfrac{6}{__}\)

Answer:

\(\dfrac{1}{2} = \dfrac{6}{12}\)

Open

Question. 30

\(-\dfrac{2}{9} - \dfrac{7}{9} = \) _____.

Answer:

\(-\dfrac{2}{9} - \dfrac{7}{9} = -1\).

Open

Question. 31

\(-\dfrac{7}{8} \; \Box \; \dfrac{8}{9}\)

Answer:

\(-\dfrac{7}{8} < \dfrac{8}{9}\)

Open

Question. 32

\(\dfrac{3}{7} \; \Box \; \dfrac{-5}{6}\)

Answer:

\(\dfrac{3}{7} > -\dfrac{5}{6}\)

Open

Question. 33

\(\dfrac{5}{6} \; \Box \; \dfrac{8}{4}\)

Answer:

\(\dfrac{5}{6} < 2\)

Open

Question. 34

\(-\dfrac{9}{7} \; \Box \; \dfrac{4}{-7}\)

Answer:

\(-\dfrac{9}{7} < -\dfrac{4}{7}\)

Open

Question. 35

\(\dfrac{8}{8} \; \Box \; \dfrac{2}{2}\)

Answer:

\(\dfrac{8}{8} = \dfrac{2}{2}\)

Open

Question. 36

The reciprocal of _____ does not exist.

Answer:

The reciprocal of zero does not exist.

Open

Question. 37

The reciprocal of 1 is _____.

Answer:

The reciprocal of 1 is 1.

Open

Question. 38

\(-\dfrac{3}{7} \div ( -\dfrac{7}{3} ) = \) _____

Answer:

\(-\dfrac{3}{7} \div ( -\dfrac{7}{3} ) = \dfrac{9}{49}\)

Open

Question. 39

\(0 \div ( -\dfrac{5}{6} ) = \) _____

Answer:

\(0 \div ( -\dfrac{5}{6} ) = 0\)

Open

Question. 40

\(0 \times ( -\dfrac{5}{6} ) = \) _____

Answer:

\(0 \times ( -\dfrac{5}{6} ) = 0\)

Open

Question. 41

_____ \(\times ( -\dfrac{2}{5} ) = 1\)

Answer:

-\dfrac{5}{2} \(\times ( -\dfrac{2}{5} ) = 1\)

Open

Question. 42

The standard form of rational number -1 is _____.

Answer:

The standard form of rational number -1 is -1.

Open

Question. 43

If m is a common divisor of a and b, then \(\dfrac{a}{b} = \dfrac{a \div m}{\_\_\_}\)

Answer:

If m is a common divisor of a and b, then \(\dfrac{a}{b} = \dfrac{a \div m}{b \div m}\).

Open

Question. 44

If p and q are positive integers, then \(\dfrac{p}{q}\) is a _____ rational number and \(\dfrac{p}{-q}\) is a _____ rational number.

Answer:

If p and q are positive integers, then \(\dfrac{p}{q}\) is a positive rational number and \(\dfrac{p}{-q}\) is a negative rational number.

Open

Question. 45

Two rational numbers are said to be equivalent or equal, if they have the same _____ form.

Answer:

Two rational numbers are said to be equivalent or equal, if they have the same simplest form.

Open

Question. 46

If \(\dfrac{p}{q}\) is a rational number, then q cannot be _____.

Answer:

If \(\dfrac{p}{q}\) is a rational number, then q cannot be zero.

Open

True or False

In questions 47 to 65, state whether the statements are True or False.

Question. 47

Every natural number is a rational number but every rational number need not be a natural number.

Answer:

true

Open

Question. 48

Zero is a rational number.

Answer:

true

Open

Question. 49

Every integer is a rational number but every rational number need not be an integer.

Answer:

true

Open

Question. 50

Every negative integer is not a negative rational number.

Answer:

false

Open

Question. 51

If \(\dfrac{p}{q}\) is a rational number and m is a non-zero integer, then \(\dfrac{p}{q} = \dfrac{p \times m}{q \times m}\).

Answer:

true

Open

Question. 52

If \(\dfrac{p}{q}\) is a rational number and m is a non-zero common divisor of p and q, then \(\dfrac{p}{q} = \dfrac{p \div m}{q \div m}\).

Answer:

true

Open

Question. 53

In a rational number, denominator always has to be a non-zero integer.

Answer:

true

Open

Question. 54

If \(\dfrac{p}{q}\) is a rational number and m is a non-zero integer, then \(\dfrac{p \times m}{q \times m}\) is a rational number not equivalent to \(\dfrac{p}{q}\).

Answer:

false

Open

Question. 55

Sum of two rational numbers is always a rational number.

Answer:

true

Open

Question. 56

All decimal numbers are also rational numbers.

Answer:

true

Open

Question. 57

The quotient of two rationals is always a rational number.

Answer:

true

Open

Question. 58

Every fraction is a rational number.

Answer:

true

Open

Question. 59

Two rationals with different numerators can never be equal.

Answer:

false

Open

Question. 60

8 can be written as a rational number with any integer as denominator.

Answer:

false

Open

Question. 61

\(\dfrac{4}{6}\) is equivalent to \(\dfrac{2}{3}\).

Answer:

true

Open

Question. 62

The rational number \(-\dfrac{3}{4}\) lies to the right of zero on the number line.

Answer:

false

Open

Question. 63

The rational numbers \(-\dfrac{12}{-5}\) and \(-\dfrac{7}{17}\) are on the opposite sides of zero on the number line.

Answer:

true

Open

Question. 64

Every rational number is a whole number.

Answer:

false

Open

Question. 65

Zero is the smallest rational number.

Answer:

false

Open

Problems and Solutions

In Questions 66 to 85, solve each problem and provide the reasoning as required.

Question. 66

66. Match the following:

Column IColumn II
(i) \(\dfrac{a}{b} \div \dfrac{a}{b}\)(a) \(-\dfrac{a}{b}\)
(ii) \(\dfrac{a}{b} \div \dfrac{c}{d}\)(b) \(-1\)
(iii) \(\dfrac{a}{b} \div (-1)\)(c) 1
(iv) \(\dfrac{a}{b} \div \dfrac{-a}{b}\)(d) \(\dfrac{bc}{ad}\)
(v) \(\dfrac{b}{a} \div (\dfrac{d}{c})\)(e) \(\dfrac{ad}{bc}\)

Answer:

(i) ↔ (c)

(ii) ↔ (e)

(iii) ↔ (a)

(iv) ↔ (b)

(v) ↔ (d)

Open

Question. 67

Write each of the following rational numbers with positive denominators: \(\dfrac{5}{-8}, \dfrac{15}{-28}, \dfrac{-17}{-13}\).

Answer:

\(\dfrac{5}{-8} = -\dfrac{5}{8}\)

\(\dfrac{15}{-28} = -\dfrac{15}{28}\)

\(\dfrac{-17}{-13} = \dfrac{17}{13}\)

Open

Question. 68

Express \(\dfrac{3}{4}\) as a rational number with denominator:

(i) 36

(ii) -80

Answer:

(i) \(\dfrac{27}{36}\)

(ii) \(\dfrac{-60}{-80}\)

Open

Question. 69

Reduce each of the following rational numbers in its lowest form:

(i) \(\dfrac{-60}{72}\)

(ii) \(\dfrac{91}{-364}\)

Answer:

(i) \(-\dfrac{5}{6}\)

(ii) \(-\dfrac{1}{4}\)

Open

Question. 70

Express each of the following rational numbers in its standard form:

(i) \(\dfrac{-12}{-30}\)

(ii) \(\dfrac{14}{-49}\)

(iii) \(\dfrac{-15}{35}\)

(iv) \(\dfrac{299}{-161}\)

Answer:

(i) \(\dfrac{2}{5}\)

(ii) \(-\dfrac{2}{7}\)

(iii) \(-\dfrac{3}{7}\)

(iv) \(-\dfrac{13}{7}\)

Open

Question. 71

Are the rational numbers \(\dfrac{-8}{28}\) and \(\dfrac{32}{-112}\) equivalent? Give reason.

Answer:

Yes, both simplify to \(-\dfrac{2}{7}\).

Open

Question. 72

Arrange the rational numbers \(-\dfrac{7}{10}, \dfrac{5}{-8}, \dfrac{2}{-3}, -\dfrac{1}{4}, -\dfrac{3}{5}\) in ascending order.

Answer:

-\dfrac{7}{10}, -\dfrac{2}{3}, -\dfrac{5}{8}, -\dfrac{3}{5}, -\dfrac{1}{4}

Open

Question. 73

Represent the following rational numbers on a number line: \(\dfrac{3}{8}, -\dfrac{7}{3}, \dfrac{22}{-6}\).

Answer:

Points marked at \(\dfrac{3}{8}\), -\dfrac{7}{3}, -\dfrac{11}{3}\) on number line.

Open

Question. 74

If \(-\dfrac{5}{7} = \dfrac{x}{28}\), find the value of x.

Answer:

\(x = -20\)

Open

Question. 75

Give three rational numbers equivalent to:

(i) \(-\dfrac{3}{4}\)

(ii) \(\dfrac{7}{11}\)

Answer:

(i) -\dfrac{6}{8}, -\dfrac{9}{12}, -\dfrac{12}{16}

(ii) \dfrac{14}{22}, \dfrac{21}{33}, \dfrac{28}{44}

Open

Question. 76

Write the next three rational numbers to complete the pattern:

(i) \(\dfrac{4}{-5}, \dfrac{8}{-10}, \dfrac{12}{-15}, \dfrac{16}{-20}, \_\_, \_\_, \_\_\)

(ii) \(\dfrac{-8}{7}, \dfrac{-16}{14}, \dfrac{-24}{21}, \dfrac{-32}{28}, \_\_, \_\_, \_\_\)

Answer:

(i) -\dfrac{20}{25}, -\dfrac{24}{30}, -\dfrac{28}{35}

(ii) -\dfrac{40}{35}, -\dfrac{48}{42}, -\dfrac{56}{49}

Open

Question. 77

List four rational numbers between \(\dfrac{5}{7}\) and \(\dfrac{7}{8}\).

Answer:

\(\dfrac{42}{56}, \dfrac{44}{56}, \dfrac{46}{56}, \dfrac{48}{56}\)

Open

Question. 78

Find the sum of:

(i) \(\dfrac{8}{13} + \dfrac{3}{11}\)

(ii) \(\dfrac{7}{3} + \dfrac{-4}{3}\)

Answer:

(i) \(\dfrac{127}{143}\)

(ii) 1

Open

Question. 79

Solve:

(i) \(\dfrac{29}{4} - \dfrac{30}{7}\)

(ii) \(\dfrac{5}{13} - \dfrac{-8}{26}\)

Answer:

(i) \(\dfrac{83}{28}\)

(ii) \(\dfrac{9}{13}\)

Open

Question. 80

Find the product of:

(i) \(\dfrac{-4}{5} \times \dfrac{-5}{12}\)

(ii) \(\dfrac{-22}{11} \times \dfrac{-21}{11}\)

Answer:

(i) \(\dfrac{1}{3}\)

(ii) \(\dfrac{42}{11}\)

Open

Question. 81

Simplify:

(i) \(\dfrac{13}{11} \times \dfrac{-14}{5} + \dfrac{13}{11} \times \dfrac{-7}{5} + \dfrac{-13}{11} \times \dfrac{34}{5}\)

(ii) \(\dfrac{6}{5} \times \dfrac{3}{7} - \dfrac{1}{5} \times \dfrac{3}{7}\)

Answer:

(i) -13

(ii) \(\dfrac{3}{7}\)

Open

Question. 82

Simplify:

(i) \(\dfrac{3}{7} \div (\dfrac{21}{-55})\)

(ii) \(1 \div ( -\dfrac{1}{2} )\)

Answer:

(i) \(-\dfrac{55}{49}\)

(ii) -2

Open

Question. 83

Which is greater in the following?

(i) \(\dfrac{3}{4}, \dfrac{7}{8}\)

(ii) -\(\dfrac{3}{5}, \dfrac{1}{9}\)

Answer:

(i) \(\dfrac{7}{8}\)

(ii) \(\dfrac{1}{9}\)

Open

Question. 84

Write a rational number in which the numerator is less than \(-7×11\) and the denominator is greater than \(12+4\).

Answer:

Examples: -\dfrac{78}{17}, -\dfrac{79}{18}

Open

Question. 85

If \(x=\dfrac{1}{10}\) and \(y=\dfrac{-3}{8}\), then evaluate \(x+y, x-y, x×y, x÷y\).

Answer:

(i) \(x+y = -\dfrac{11}{40}\)

(ii) \(x-y = \dfrac{19}{40}\)

(iii) \(x×y = -\dfrac{3}{80}\)

(iv) \(x÷y = -\dfrac{4}{15}\)

Open

Question. 86

Find the reciprocal of the following:

(i) \((\dfrac{1}{2} \times \dfrac{1}{4}) + (\dfrac{1}{2} \times 6)\)

(ii) \(\dfrac{20}{51} \times \dfrac{4}{91}\)

(iii) \(\dfrac{3}{13} \div \dfrac{-4}{65}\)

(iv) \((-5 \times \dfrac{12}{15}) - (-3 \times \dfrac{2}{9})\)

Answer:

(i) \(\dfrac{8}{25}\)

(ii) \(\dfrac{4641}{80}\)

(iii) \(-\dfrac{4}{15}\)

(iv) \(-\dfrac{3}{10}\)

Open

Question. 87

Complete the following table by finding the sums:

Answer:

+-1/94/11-5/6
2/35/934/33-1/6
-5/4-49/36-39/44-25/12
-1/3-4/91/33-7/6

Open

Question. 88

Write each of the following numbers in the form \(\dfrac{p}{q}\):

(a) six-eighths

(b) three and half

(c) opposite of 1

(d) one-fourth

(e) zero

(f) opposite of three-fifths

Answer:

(a) \(\dfrac{6}{8}\)

(b) \(\dfrac{7}{2}\)

(c) \(-1\)

(d) \(\dfrac{1}{4}\)

(e) \(0\)

(f) \(-\dfrac{3}{5}\)

Open

Question. 89

If \(p = m \times t\) and \(q = n \times t\), then \(\dfrac{p}{q} = \_\_\).

Answer:

\(\dfrac{p}{q} = \dfrac{m}{n}\)

Open

Question. 90

Given \(\dfrac{p}{q}\) and \(\dfrac{r}{s}\) are rationals in standard form:

(a) \(\dfrac{p}{q} < \dfrac{r}{s}\), if \(p \times s < r \times q\)

(b) \(\dfrac{p}{q} = \dfrac{r}{s}\), if \(p \times s = r \times q\)

(c) \(\dfrac{p}{q} > \dfrac{r}{s}\), if \(p \times s > r \times q\)

Answer:

(a) \(\dfrac{p}{q} < \dfrac{r}{s}\)

(b) \(p \times s = r \times q\)

(c) \(\dfrac{p}{q} > \dfrac{r}{s}\)

Open

Question. 91

In each of the following cases, write the rational number whose numerator and denominator are respectively as under:

(a) 5–39 and 54–6

(b) (-4)×6 and 8÷2

(c) 35÷(-7) and 35–18

(d) 25+15 and 81÷40

Answer:

(a) -34/48

(b) -24/4

(c) -5/17

(d) 1600/81

Open

Question. 92

Write the following as rational numbers in their standard forms:

(a) 35%

(b) 1.2

(c) -6 3/7

(d) 240 ÷ (-840)

(e) 115 ÷ 207

Answer:

(a) 7/20

(b) 6/5

(c) -45/7

(d) -2/7

(e) 5/9

Open

Question. 93

Find a rational number exactly halfway between:

(a) -1/3 and 1/3

(b) 1/6 and 1/9

(c) 5/-13 and -7/9

(d) 1/15 and 1/12

Answer:

(a) 0

(b) 5/36

(c) -136/234

(d) 3/40

Open

Question. 94

Taking x=-4/9, y=5/12, z=7/18, find:

(a) rational number added to x gives y

(b) rational number subtracted from y gives z

(c) rational number added to z gives x

(d) rational number multiplied by y gives x

(e) reciprocal of x+y

(f) sum of reciprocals of x and y

(g) (x÷y)×z

(h) (x–y)+z

(i) x+(y+z)

(j) x ÷ (y ÷ z)

(k) x–(y+z)

Answer:

(a) 31/36

(b) 1/36

(c) -5/6

(d) -48/45

(e) -36

(f) 3/20

(g) -56/135

(h) -17/36

(i) 13/36

(j) -56/135

(k) -5/4

Open

Question. 95

What should be added to -1/2 to obtain the nearest natural number?

Answer:

3/2

Open

Question. 96

What should be subtracted from -2/3 to obtain the nearest integer?

Answer:

1/3

Open

Question. 97

What should be multiplied with -5/8 to obtain the nearest integer?

Answer:

8/5

Open

Question. 98

What should be divided by 1/2 to obtain the greatest negative integer?

Answer:

-1/2

Open

Question. 99

A rope 68m long is cut into pieces of length 4 1/4 m. Find number of such pieces.

Answer:

16

Open

Question. 100

If 12 shirts of equal size are prepared from 27m cloth, what is length required for each shirt?

Answer:

2.25 m

Open

Question. 101

Insert 3 equivalent rational numbers between:

(i) -1/2 and 1/5

(ii) 0 and -10

Answer:

(i) -3/20, -6/40, -9/60

(ii) -5, -10/2, -15/3

Open

Question. 102

Put (√) wherever applicable:

NumberNaturalWholeIntegerFractionRational
-114
19/27
623/1
-19 3/4
73/71
0

Answer:

As shown in the table above.

Open

Question. 103

a and b are different numbers from 1–50. What is largest value of (a–b)/(a+b) and (a+b)/(a–b)?

Answer:

49/51 and 99

Open

Question. 104

150 students study English, Maths or both. 62% study English, 68% study Maths. How many study both?

Answer:

45

Open

Question. 105

A body floats 2/9 above surface. What is ratio of submerged volume to exposed volume?

Answer:

7:2 or 7/2

Open

Question. 106

Find the odd one out:

(a) 4/3×3/4

(b) -3/2×-2/3

(c) 2×1/2

(d) -1/3×3/1

Answer:

(d)

Open

Question. 107

Find the odd one out:

(a) 4/-9

(b) -16/36

(c) -20/-45

(d) 28/-63

Answer:

(c)

Open

NCERT Exemplar Solutions Class 7 – Mathematics – Unit 8: Rational Numbers | Detailed Answers