ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Check Your Progress

ML Aggarwal Class 7 Solutions Chapter 3 Rational Numbers Check Your Progress for ICSE Understanding Mathematics acts as the best resource during your learning and helps you score well in your exams.

ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Check Your Progress

Question 1.
Write five rational numbers equivalent to \(\frac { 5 }{ -11 }\)
Solution:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Check Your Progress 1

Question 2.
Express \(\frac { 9 }{ -15 }\) as a rational number with:
(i) denominator 5
(ii) numerator -12
(iii) denominator 30
Solution:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Check Your Progress 2

Question 3.
Write each of the following numbers in standard form:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Check Your Progress 3
Solution:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Check Your Progress 4

Question 4.
Which of the following are pairs of equivalent rational numbers?
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Check Your Progress 5
Solution:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Check Your Progress 6
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Check Your Progress 7

Question 5.
Arrange the following rational numbers in ascending order:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Check Your Progress 8
Solution:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Check Your Progress 9
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Check Your Progress 10

Question 6.
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Check Your Progress 11
Solution:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Check Your Progress 12

Question 7.
Insert five rational numbers between \(\frac { -3 }{ 5 }\) and \(\frac { -1 }{ 2 }\).
Solution:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Check Your Progress 13

Question 8.
Find the sum:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Check Your Progress 14
Solution:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Check Your Progress 15

Question 9.
Subtract:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Check Your Progress 16
Solution:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Check Your Progress 17
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Check Your Progress 18

ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Objective Type Questions

ML Aggarwal Class 7 Solutions Chapter 3 Rational Numbers Objective Type Questions for ICSE Understanding Mathematics acts as the best resource during your learning and helps you score well in your exams.

ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Objective Type Questions

Mental Maths

Question 1.
Fill in the blanks:
(i) Two rational numbers are called equivalent if they have …… value.
(ii) The number \(\frac { -4 }{ 7 }\) lies to the …….. of zero on the number line.
(iii) The rational number \(\frac { -5 }{ -11 }\) lies to the ……. of zero on the number line.
(iv) The rational number \(\frac { -84 }{ 156 }\) reduced to simplest form is ………
(v) The standard form of the rational number \(\frac { 14 }{ -12 }\) is ………
(vi) There are ….. rational numbers between two different rational numbers.
(vii) Two rational numbers \(\frac { p }{ q }\)and \(\frac { r }{ s }\) are equal if an only if q × r = ……..
(viii)The multiplicative inverse of -3\(\frac { 1 }{ 5 }\) is ……..
(ix) \(\frac { -3 }{ 7 }\) ÷ \(\frac { -7 }{ 3 }\) = ………
(x) If p and q are positive integers, then \(\frac { p }{ q }\) is a …… rational number and \(\frac { p }{ -q }\) is a ……
Solution:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Objective Type Questions 1

Question 2.
State whether the following statements are true (T) or false (F).
(i) Zero is the smallest rational number.
(ii) Every integer is a rational number.
(iii) Every rational number is an integer.
(iv) Every fraction is a rational number.
(v) Every rational number is a fraction.
(vi) The reciprocal of -1 is -1.
(vii) The quotient of two integers is always a rational number.
(viii) The value of a rational number remains the same if both its numerator and denominator are multiplied (or divided) by the same (nonzero) integer.
(ix) Between two distinct integers, we can always insert an integer.
(x) Between two distinct rational numbers, we can al ways insert a rational number.
(xi) There exists atleast one integer between two different rational numbers.
(xii) The reciprocal of 2\(\frac { 6 }{ 7 }\) is \(\frac { -7}{ 20 }\).
(xiii) All terminating decimal numbers are rational numbers.
Solution:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Objective Type Questions 2
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Objective Type Questions 3

Multiple Choice Questions

Choose the correct answer from the given four options (3 to 14):
Question 3.
The rational number \(\frac { 110 }{ -132 }\) when reduced to standard form is
(a) \(\frac { 10 }{ -12 }\)
(b) \(\frac { 5 }{ -6 }\)
(c) \(\frac { -5 }{ 6 }\)
(d) \(\frac { 110 }{ -132 }\)
Solution:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Objective Type Questions 4

Question 4.
The Additive inverse of \(\frac { -7 }{ 12 }\) is
(a) \(\frac { 12 }{ -7 }\)
(b) \(\frac { -7 }{ 12 }\)
(c) \(\frac { -5 }{ 12 }\)
(d) \(\frac { 7 }{ 12 }\)
Solution:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Objective Type Questions 5

Question 5.
The Multiplicative inverse of \(\frac { -4 }{ 9 }\) is
(a) \(\frac { 4 }{ 9 }\)
(b) \(\frac { -9 }{ 4 }\)
(c) \(\frac { 9 }{ 4 }\)
(d) none of these
Solution:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Objective Type Questions 6

Question 6.
The reciprocal of the rational number -2\(\frac { 3 }{ 7 }\) is
(a) \(\frac { -17 }{ 7 }\)
(b) \(\frac { 7 }{ 17 }\)
(c) \(\frac { -7 }{ 17 }\)
(d) none of these
Solution:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Objective Type Questions 7

Question 7.
The product of rational number \(\frac { -2 }{ 5 }\) and its multiplicative inverse is
(a) 1
(b) 0
(c) \(\frac { 4 }{ 25 }\)
(d) \(\frac { 2 }{ 5 }\)
Solution:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Objective Type Questions 8

Question 8.
The product of rational number \(\frac { -2 }{ 3 }\) and its additive inverse is
(a) 1
(b) \(\frac { 2 }{ 3 }\)
(c) \(\frac { 4 }{ 9 }\)
(d) \(\frac { -4 }{ 9 }\)
Solution:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Objective Type Questions 9

Question 9.
The sum of rational number \(\frac { -1 }{ 3 }\) and its reciprocal is
(a) 0
(b) 1
(c) \(\frac { -10 }{ 3 }\)
(d) \(\frac { -3 }{ 10 }\)
Solution:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Objective Type Questions 10

Question 10.
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Objective Type Questions 11
Solution:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Objective Type Questions 12

Question 11.
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Objective Type Questions 13
Solution:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Objective Type Questions 14

Question 12.
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Objective Type Questions 15
Solution:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Objective Type Questions 16

Question 13.
In the standard form of a rational number, the denominator is always
(a) 0
(b) a negative integer
(c) 1
(d) a positive integer
Solution:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Objective Type Questions 17

Question 14.
The sum of two rational numbers is -1. If one of them is \(\frac { -5 }{ 7 }\), then the other is
(a) \(\frac { 5 }{ 7 }\)
(b) \(\frac { -2 }{ 7 }\)
(c) \(\frac { 12 }{ 7 }\)
(d) \(\frac { -12 }{ 7 }\)
Solution:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Objective Type Questions 18

Value Based Questions

Question 1.
Rohit donated \(\frac { 1 }{ 5 }\) of his monthly income to an NGO working for the education of old women, \(\frac { 1 }{ 4 }\) of his salary spent on food, \(\frac { 1 }{ 3 }\) on rent and \(\frac { 1 }{ 15 }\) on other expenses. If he is left with ₹ 9000, find his monthly income. What values are being promoted?
Solution:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Objective Type Questions 19
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Objective Type Questions 20

Higher Order Thinking Skills (HOTS)

Question 1.
From a rope 15 m long, 4\(\frac { 1 }{ 3 }\) m is cut off and \(\frac { 3 }{ 5 }\) of the remaining is cut off again. Find the length of the remaining part of the rope.
Solution:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Objective Type Questions 21

Question 2.
Perimeter of a rectangle is 2 m less than \(\frac { 2 }{ 5 }\) of the perimeter of a square, if the perimeter of the square is 40 m, find the length and breadth of the rectangle given that the breadth is \(\frac { 1 }{ 3 }\) of the length.
Solution:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Objective Type Questions 22

ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.3

ML Aggarwal Class 7 Solutions Chapter 3 Rational Numbers Ex 3.3 for ICSE Understanding Mathematics acts as the best resource during your learning and helps you score well in your exams.

ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.3

Question 1.
Add the following pairs of rational numbers:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.3 1
Solution:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.3 2
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.3 3

Question 2.
Find the sum:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.3 4
Solution:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.3 5
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.3 6
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.3 7

Question 3.
Subtract:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.3 8
Solution:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.3 9

Question 4.
Find:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.3 10
Solution:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.3 11
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.3 12

Question 5.
The sum of two rational numbers is \(\frac { 2 }{ 5 }\) if one of them is \(\frac { -4 }{ 7 }\), find the other.
Solution:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.3 13

Question 6.
What rational number should be added to \(\frac { -5 }{ 12 }\) to get \(\frac { -7 }{ 8 }\)?
Solution:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.3 14

Question 7.
What rational number should be subtracted from \(\frac { -2 }{ 3 }\) to get \(\frac { -5 }{ 6 }\)?
Solution:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.3 15

Question 8.
Find the product:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.3 16
Solution:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.3 17
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.3 18

Question 9.
Find the value of:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.3 19
Solution:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.3 20
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.3 21

Question 10.
The product of two rational numbers is \(\frac { 18 }{ 35 }\) If one of them is \(\frac { -2 }{ 5 }\), find the other.
Solution:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.3 22

Question 11.
Find the value of:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.3 23
Solution:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.3 24
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.3 25

Question 12.
Find the reciprocal of the following:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.3 26
Solution:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.3 27

ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.2

ML Aggarwal Class 7 Solutions Chapter 3 Rational Numbers Ex 3.2 for ICSE Understanding Mathematics acts as the best resource during your learning and helps you score well in your exams.

ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.2

Question 1.
Draw a number line and represent the following rational numbers on it:
(i) \(\frac { 3 }{ 8 }\)
(ii) \(\frac { -3 }{ 4 }\)
(iii) \(\frac { -7 }{ 8 }\)
(iv) \(\frac { -17 }{ 8 }\)
Solution:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.2 1

Question 2.
The points P, Q, R, S, T, U, A and B on the number line are such that TR = RS = SU and AP = PQ = QB. Name the rational numbers represented by P, Q, R and S respectively.
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.2 2
Solution:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.2 3

Question 3.
State whether the following statements are true or false:
(i) The rational number \(\frac { -13 }{ -5 }\) lies to the right of zeroxin the number line.
(ii) The rational numbers \(\frac { -5 }{ -7 }\) and \(\frac { 7 }{ -9 }\) lie on opposite sides of zero on the number line.
(iii) The rational numbers \(\frac { -17 }{ 6 }\) and \(\frac { 8 }{ -15 }\) lie on opposite sides of zero on the number line.
Solution:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.2 4

Question 4.
Which of the two rational numbers is greater in each of tl following pairs?
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.2 5
Solution:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.2 6

Question 5.
Fill in the boxes with the correct symbol out of >, < and =:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.2 7
Solution:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.2 8
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.2 9
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.2 10
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.2 11

Question 6.
Arrange the following rational numbers in ascending order:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.2 12
Solution:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.2 13
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.2 14

Question 7.
Arrange the following rational numbers in descending order:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.2 15
Solution:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.2 16
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.2 17

Question 8.
Insert five rational numbers between:
(i) -3 and -2
(ii) \(\frac { -2 }{ 3 }\) and \(\frac { -1 }{ 3 }\)
Solution:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.2 18
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.2 19

Question 9.
Insert five rational numbers between:
(i) \(\frac { -4 }{ 5 }\) and [lat3.1
ex]\frac { -2 }{ 3 }[/latex]
(ii) \(\frac { -1 }{ 2 }\) and \(\frac { 2 }{ 3 }\)
Solution:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.2 20
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.2 21

ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.1

ML Aggarwal Class 7 Solutions Chapter 3 Rational Numbers Ex 3.1 for ICSE Understanding Mathematics acts as the best resource during your learning and helps you score well in your exams.

ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.1

Question 1.
Which of the following are positive rational numbers?
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.1 1
Solution:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.1 2

Question 2.
Which of the following are negative rational numbers?
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.1 3
Solution:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.1 4

Question 3.
Find four rational numbers equivalent to each of the following rational numbers:
(i) \(\frac { 3 }{ -7 }\)
(ii) \(\frac { -5 }{ -9 }\)
Solution:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.1 5
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.1 6
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.1 7

Question 4.
Write each of the following ratinoal numbers with positive denominators:
(i) \(\frac { 4 }{ -9 }\)
(ii) \(\frac { 17 }{ -33 }\)
(iii) \(\frac { -15 }{ -38 }\)
Solution:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.1 8

Question 5.
Write next four rational numbers in each of the following patterns:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.1 9
Solution:
Next four rational numbers in the same patterns.
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.1 10

Question 6.
Which of the following pairs of rational numbers are equal?
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.1 11
Solution:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.1 12
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.1 13

Question 7.
Which of the following pairs represent the same rational number?
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.1 14
Solution:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.1 15
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.1 16
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.1 17

Question 8.
Fill in the blanks:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.1 18
Solution:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.1 19

Question 9.
Reduce each of the following rational numbers in standard form:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.1 20
Solution:
ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 3 Rational Numbers Ex 3.1 21