Real Numbers is a chapter in the CBSE Class 10 Mathematics syllabus from Mathematics. This chapter hub brings together revision notes, practice questions, worksheets, flashcards, formula sheet to help students learn, practice, and revise Real Numbers effectively.

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Real Numbers

NCERT Class 10 Mathematics Chapter 1: Real Numbers (Pages 1–8)

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Summary of Real Numbers

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Real Numbers at a Glance

Board

CBSE

Class

Class 10

Subject

Mathematics

Book

Mathematics

Chapter

1

Pages

18

Resources

7 study resources

Real Numbers Summary

In this chapter, you will explore the concept of real numbers, building on what you learned in Class IX about irrational numbers. We will revisit key ideas like Euclid's division algorithm, which helps us understand how to divide positive integers and find remainders. This algorithm states that for any integer 'a' divided by another integer 'b', the result leaves a remainder 'r' that is smaller than 'b'. This understanding leads to practical applications, particularly in calculating the highest common factor (HCF) of two positive integers. You will also learn about the Fundamental Theorem of Arithmetic, which tells us that every composite number can be uniquely expressed as a product of prime numbers. This theorem has profound implications for both number theory and practical mathematics, as it provides the foundation for understanding how numbers relate to one another when multiplied or divided. Furthermore, the chapter dives into irrational numbers, demonstrating their existence and characteristics. Rational numbers can be expressed in the form of a fraction, but irrational numbers cannot. Examples of irrational numbers include the square root of two, three, and five. We will prove that these numbers are irrational, employing methods that show contradictions arising from incorrect assumptions. Throughout the chapter, you will engage with exercises that strengthen your understanding of these concepts. Exercises include expressing numbers as products of their prime factors and finding HCF and LCM using prime factorizations. These are foundational skills that will serve you well in future mathematical studies. You will also explore the nature of decimal expansions and learn how to determine whether a decimal is terminating or repeating by examining the prime factors of its denominator. This exploration ties the concepts of rational and irrational numbers to real-world applications, enhancing your mathematical toolkit. As you progress through the lessons, pay close attention to the proofs and examples provided, as they illustrate the real-world relevance of the concepts you've learned. Understanding these relationships and their applications will help you appreciate the structure and beauty of mathematics.

Real Numbers Revision Guide

Download the Real Numbers revision guide with key points, summaries, and quick revision notes for CBSE Class 10 Mathematics.

Key Points

1

Real Numbers consist of both rationals and irrationals.

Real numbers include all rational numbers (integers, fractions) and irrational numbers (cannot be expressed as a fraction). Examples: √2, π.

2

Define Euclid’s Division Theorem.

Euclid’s Division Theorem states that for any integers 'a' and 'b' (b ≠ 0), there exist unique integers 'q' and 'r' such that a = bq + r, with 0 ≤ r < b.

3

Fundamental Theorem of Arithmetic.

Every composite number can be expressed as a product of primes uniquely. For instance, 60 = 2² × 3 × 5.

4

Prime Factorization is crucial.

The HCF and LCM of numbers can be calculated using their prime factorizations, aiding results in number theory.

5

HCF and LCM relationship.

HCF(a, b) × LCM(a, b) = a × b for any two integers a and b. This relationship helps solve various problems.

6

Identify rational vs. irrational numbers.

Rational numbers can be expressed as p/q (where p, q are integers, q ≠ 0). Irrationals cannot be expressed in such a form.

7

Irrational numbers: Examples.

Common examples include √2, √3, π. They cannot be precisely represented as fractions.

8

Decimal expansion of rational numbers.

Rational numbers have either terminating or repeating decimal expansions. Check denominators’ prime factors for analysis.

9

Prove √2 is irrational.

Assume √2 = p/q leads to a contradiction, proving √2 is irrational. This involves prime factor analysis.

10

Prove √3 is irrational.

Similar to √2, assuming √3 = p/q leads to contradictions through the prime factor method, proving its irrationality.

11

Consider properties of rational/irrational sums.

The sum or difference of a rational and an irrational number is irrational. E.g., 5 + √2 is irrational.

12

Rationality of roots of primes.

Roots of prime numbers, such as √p, where p is prime, are always irrational.

13

Express numbers as prime factors.

Use factor trees to express numbers like 180 = 2² × 3² × 5, aiding in LCM/HCF calculations.

14

Applications of the Fundamental Theorem.

Helps in proving properties related to numbers and is integral in various mathematical proofs.

15

Roots: Whole numbers and their squares.

A perfect square has a whole number root, and its irrational counterpart matters in number theory.

16

Understanding non-terminating decimals.

Non-terminating decimals indicate irrationality and occur with roots of non-perfect squares.

17

Euclid's Algorithm for HCF.

An effective method using the division theorem to find HCF, making large computations manageable.

18

Laws of exponents in factorization.

Understanding properties like a^m × a^n = a^(m+n) aids in efficient factorization.

19

Visualize the number line.

Imagining the number line helps understand where irrationals fit between rationals, enhancing comprehension.

20

Factorial numbers and primes.

The product of sequential numbers (factorials) and their connections to primes helps in discrete mathematics.

Real Numbers Practice Questions & Answers

Practice important questions and exam-style problems from Real Numbers. These questions cover key topics from the CBSE Class 10 Mathematics syllabus.

How to practice: Start with the questions below to test your understanding of Real Numbers. Use the revision guide to review concepts you find difficult, then come back and retry the questions for better retention.

View all 210 Real Numbers questions
Q9

Which of the following numbers is irrational?

Single Answer MCQ
Q-00173550
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Q10

Which of the following numbers is NOT a prime factor of 45?

Single Answer MCQ
Q-00173551
View explanation
Q11

What is the LCM of 8 and 12?

Single Answer MCQ
Q-00173553
View explanation
Q12

What is the least common multiple (LCM) of 12 and 15 using their prime factorization?

Single Answer MCQ
Q-00173552
View explanation
Q13

Given that HCF(18, 24) = 6, find LCM(18, 24).

Single Answer MCQ
Q-00173554
View explanation
Q14

For which value of n does 6^n end in 0?

Single Answer MCQ
Q-00173555
View explanation
Q15

How is the prime factorization of 60 represented?

Single Answer MCQ
Q-00173556
View explanation
Q16

Which pair of numbers has the same prime factors?

Single Answer MCQ
Q-00173557
View explanation
Q17

What is √75 expressed in simplest form?

Single Answer MCQ
Q-00173558
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Q18

Which number cannot be expressed as a product of prime numbers according to the Fundamental Theorem of Arithmetic?

Single Answer MCQ
Q-00173559
View explanation
Q19

What is the product of HCF and LCM of two numbers equal to?

Single Answer MCQ
Q-00173560
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Q20

If the prime factorization of a number is of the form p^a × q^b where p and q are primes, what can be said about it?

Single Answer MCQ
Q-00173561
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Q21

If p is a prime factor of n², what can be inferred about n?

Single Answer MCQ
Q-00173563
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Q22

Which of the following is true regarding irrational numbers?

Single Answer MCQ
Q-00173562
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Q23

Which of the following numbers is irrational?

Single Answer MCQ
Q-00173565
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Q24

Which equation demonstrates that √2 is irrational?

Single Answer MCQ
Q-00173564
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Q25

Which of the following is a true application of the Fundamental Theorem of Arithmetic?

Single Answer MCQ
Q-00173566
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Q26

The number 44 can be factored as 2² × 11. What is one possible composite number formed using these prime factors?

Single Answer MCQ
Q-00173567
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Q27

How many distinct prime factors does the number 126 have?

Single Answer MCQ
Q-00173568
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Q28

Can a composite number exist with only one prime factor?

Single Answer MCQ
Q-00173569
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Q29

What is a real number?

Single Answer MCQ
Q-00173570
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Q30

Which of the following is NOT a real number?

Single Answer MCQ
Q-00173571
View explanation
Q31

Which statement about the Fundamental Theorem of Arithmetic is true?

Single Answer MCQ
Q-00173572
View explanation
Q32

In the context of Euclid's division algorithm, if a = 17 and b = 5, what is the remainder?

Single Answer MCQ
Q-00173573
View explanation
Q33

When does the decimal expansion of a rational number terminate?

Single Answer MCQ
Q-00173574
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Q34

Which of the following numbers has a non-terminating decimal expansion?

Single Answer MCQ
Q-00173575
View explanation
Q35

How can you find the HCF of 48 and 180 using Euclid's division algorithm?

Single Answer MCQ
Q-00173576
View explanation
Q36

The expression √3 is an example of which type of number?

Single Answer MCQ
Q-00173577
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Q37

What does the geometric representation of real numbers depict?

Single Answer MCQ
Q-00173578
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Q38

Which of the following is true regarding rational numbers?

Single Answer MCQ
Q-00173579
View explanation
Q39

If p = 12 and q = 18, what is the HCF of p and q?

Single Answer MCQ
Q-00173580
View explanation
Q40

What does Euclid's Division Algorithm state about two positive integers 'a' and 'b'?

Single Answer MCQ
Q-00173581
View explanation
Q41

Which of the following numbers is NOT a prime number?

Single Answer MCQ
Q-00173583
View explanation
Q42

If 50 is divided by 8, what is the remainder according to Euclid's Algorithm?

Single Answer MCQ
Q-00173582
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Q43

How does one represent a non-repeating decimal?

Single Answer MCQ
Q-00173585
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Q44

Which of the following represents the correct equation based on Euclid's Division Algorithm?

Single Answer MCQ
Q-00173584
View explanation
Q45

How can Euclid's Division Algorithm be used to find the HCF of two numbers?

Single Answer MCQ
Q-00173586
View explanation
Q46

What is the decimal equivalent of the fraction 3/8?

Single Answer MCQ
Q-00173587
View explanation
Q47

Using Euclid's algorithm, what is the HCF of 56 and 98?

Single Answer MCQ
Q-00173588
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Q48

What property does Euclid's algorithm demonstrate?

Single Answer MCQ
Q-00173589
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Q49

If a = 70 and b = 35, what is the remainder when a is divided by b using Euclid's algorithm?

Single Answer MCQ
Q-00173590
View explanation
Q50

What is the first prime factor of 60?

Single Answer MCQ
Q-00173591
View explanation
Q51

If a number is expressed as p/q where q = 10, what is its decimal nature?

Single Answer MCQ
Q-00173592
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Q52

What is the main advantage of using Euclid's Division Algorithm?

Single Answer MCQ
Q-00173593
View explanation
Q53

Which step correctly follows Euclid's Division Algorithm process for finding HCF?

Single Answer MCQ
Q-00173594
View explanation
Q54

What is the HCF of 24 and 36 using Euclid's Division Algorithm?

Single Answer MCQ
Q-00173595
View explanation
Q55

In applying Euclid's Division Algorithm to find HCF, which equation is used?

Single Answer MCQ
Q-00173596
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Q56

If the remainder when dividing 90 by 11 is 2, what can you conclude using Euclid's Theorem?

Single Answer MCQ
Q-00173597
View explanation
Q57

Using Euclid's algorithm, what is the HCF of 81 and 27?

Single Answer MCQ
Q-00173598
View explanation
Q58

For two numbers 144 and 60, what is one of the stages in using Euclid's algorithm?

Single Answer MCQ
Q-00173599
View explanation
Q59

Using Euclid's algorithm, what is the first remainder when finding the HCF of 54 and 24?

Single Answer MCQ
Q-00173600
View explanation
Q60

Which of the following numbers is irrational?

Single Answer MCQ
Q-00173601
View explanation
Q61

What is the value of √2 + √3?

Single Answer MCQ
Q-00173602
View explanation
Q62

Can √18 be expressed as a simple fraction?

Single Answer MCQ
Q-00173603
View explanation
Q63

If a rational number is added to √2, what will the result be?

Single Answer MCQ
Q-00173604
View explanation
Q64

What type of number is √-4?

Single Answer MCQ
Q-00173605
View explanation
Q65

Which of the following represents an irrational number?

Single Answer MCQ
Q-00173606
View explanation
Q66

How is √5 categorized?

Single Answer MCQ
Q-00173607
View explanation
Q67

If a number is both rational and irrational, what can be concluded?

Single Answer MCQ
Q-00173608
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Q68

Which statement about irrational numbers is true?

Single Answer MCQ
Q-00173609
View explanation
Q69

What defines an irrational number?

Single Answer MCQ
Q-00173610
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Q70

Which of the following sums results in an irrational number?

Single Answer MCQ
Q-00173611
View explanation
Q71

Which expression is definitely irrational?

Single Answer MCQ
Q-00173612
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Q72

Prove that √3 is irrational using what theorem?

Single Answer MCQ
Q-00173613
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Q73

Which statement about squares of irrational numbers is correct?

Single Answer MCQ
Q-00173614
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Q74

Is it possible for a rational number and an irrational number to multiply to a rational number?

Single Answer MCQ
Q-00173615
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Q75

What can we conclude about the roots of prime numbers?

Single Answer MCQ
Q-00173616
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Q76

Confirm the result of √2 + √3. What does it signify?

Single Answer MCQ
Q-00173617
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Q77

If HCF of 66 and 99 is expressible in the form of 55m - 132, then the value of m is:

Single Answer MCQ
Q-00200586
View explanation
Q78

Two numbers are in the ratio 3 : 5 and their LCM is 180. Find the HCF of these two numbers.

Text
Q-00200590
View explanation
Q79

Prove that 2 + (3√5)/7 is an irrational number, given that √5 is an irrational number.

Text
Q-00200594
View explanation
Q80

7 × 29 × 23 + 1 is:

Single Answer MCQ
Q-00200608
View explanation
Q81

If HCF (850, 325) is 25, then LCM (850, 325) is:

Single Answer MCQ
Q-00200613
View explanation
Q82

Assertion (A): 4^n cannot end with the digit zero. Reason (R): Prime factorisation of 4^n is unique.

Single Answer MCQ
Q-00200617
View explanation
Q83

Prove that √5 is an irrational number.

Text
Q-00200626
View explanation
Q84

For any natural number n, 6^n ends with the digit:

Single Answer MCQ
Q-00200847
View explanation
Q85

The natural number 2 is:

Single Answer MCQ
Q-00200848
View explanation
Q86

The HCF of 960 and 432 is:

Single Answer MCQ
Q-00200849
View explanation
Q87

Prove that √2 is an irrational number.

Text
Q-00200874
View explanation
Q88

If the HCF of two positive integers a and b is 1, then their LCM is:

Single Answer MCQ
Q-00201022
View explanation
Q89

The number 3 + √2 is:

Single Answer MCQ
Q-00201024
View explanation
Q90

Assertion (A): For any two natural numbers a and b, the HCF of a and b is a factor of the LCM of a and b. Reason (R): HCF of any two natural numbers divides both the numbers.

Single Answer MCQ
Q-00201044
View explanation
Q91

Prove that √3 is an irrational number.

Text
Q-00201049
View explanation
Q92

The factor tree of a number x is shown. Find the values of x, y, a and b. Hence, write the product of the prime factors of the number x so obtained.

Text
Q-00201050
View explanation
Q93

Assertion (A): H.C.F. (36m², 18m) = 18m, where m is a prime number. Reason (R): H.C.F. of two numbers is always less than or equal to the smaller number.

Single Answer MCQ
Q-00201154
View explanation
Q94

Prove that 14 − 2√3 is an irrational number, given that √3 is irrational.

Text
Q-00201160
View explanation
Q95

The dimensions of a window are 156 cm × 216 cm. Arjun wants to put grill on the window creating complete squares of maximum size. Determine the side length of the square and hence find the number of squares formed.

Text
Q-00201168
View explanation
Q96

The LCM of 960 and 240 is:

Single Answer MCQ
Q-00201189
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Q97

The natural number 1 is:

Single Answer MCQ
Q-00201188
View explanation
Q98

For any natural number n, 5^n ends with the digit:

Single Answer MCQ
Q-00201190
View explanation
Q99

Prove that √5 is an irrational number.

Text
Q-00201214
View explanation
Q100

There are two sections A and B of Grade X. There are 28 students in Section A and 30 students in Section B. What is the minimum number of books you will acquire for the class library so that they can be distributed equally among students of Section A or Section B?

Single Answer MCQ
Q-00201473
View explanation
Q101

The natural number 1 is:

Single Answer MCQ
Q-00201476
View explanation
Q102

For any natural number n, 5^n ends with the digit:

Single Answer MCQ
Q-00201475
View explanation
Q103

Prove that √5 is an irrational number.

Text
Q-00201503
View explanation
Q104

The natural number 1 is:

Single Answer MCQ
Q-00201527
View explanation
Q105

For any natural number n, 5^n ends with the digit:

Single Answer MCQ
Q-00201528
View explanation
Q106

The LCM of 960 and 240 is:

Single Answer MCQ
Q-00201530
View explanation
Q107

Prove that √5 is an irrational number.

Text
Q-00201555
View explanation
Q108

(3 × 11 × 13 + 3) is:

Single Answer MCQ
Q-00201641
View explanation
Q109

Find the length of the plank that can be used to measure the lengths 4 m 20 cm and 5 m 4 cm exactly, in the least time.

Text
Q-00201659
View explanation
Q110

Prove that √5 is an irrational number.

Text
Q-00201670
View explanation
Q111

(3 × 11 × 13 + 3) is:

Single Answer MCQ
Q-00204121
View explanation
Q112

Find the length of the plank that can be used to measure the lengths 4 m 20 cm and 5 m 4 cm exactly, in the least time.

Number
Q-00204127
View explanation
Q113

Prove that √3 is an irrational number.

Text
Q-00204139
View explanation
Q114

Arrange the following events in chronological order and choose the correct option: I. Salt Satyagraha II. Kheda Satyagraha III. Rowlatt Satyagraha IV. Ahmedabad Mill Workers Satyagraha

Single Answer MCQ
Q-00204148
View explanation
Q115

(3 × 11 × 13 + 3) is:

Single Answer MCQ
Q-00204158
View explanation
Q116

Find the length of the plank that can be used to measure the lengths 4 m 20 cm and 5 m 4 cm exactly, in the least time.

Text
Q-00204172
View explanation
Q117

Prove that √2 is an irrational number.

Text
Q-00204176
View explanation
Q118

For any natural number n, 6^n ends with the digit:

Single Answer MCQ
Q-00204205
View explanation
Q119

The HCF of 960 and 432 is:

Single Answer MCQ
Q-00204206
View explanation
Q120

The natural number 2 is:

Single Answer MCQ
Q-00204207
View explanation
Q121

Prove that √3 is an irrational number.

Text
Q-00204232
View explanation
Q122

For any natural number n, 6^n ends with the digit:

Single Answer MCQ
Q-00204259
View explanation
Q123

The HCF of 960 and 432 is:

Single Answer MCQ
Q-00204274
View explanation
Q124

The natural number 2 is:

Single Answer MCQ
Q-00204275
View explanation
Q125

Prove that √3 is an irrational number.

Text
Q-00204297
View explanation
Q126

If the HCF of two positive integers a and b is 1, then their LCM is:

Single Answer MCQ
Q-00205185
View explanation
Q127

The number (√3 – 2)/√3 is:

Single Answer MCQ
Q-00205187
View explanation
Q128

Assertion (A): For any two natural numbers a and b, the HCF of a and b is a factor of the LCM of a and b. Reason (R): HCF of any two natural numbers divides both the numbers.

Single Answer MCQ
Q-00205193
View explanation
Q129

Prove that √3 is an irrational number.

Text
Q-00205206
View explanation
Q130

The factor tree of a number x is shown. Find the values of x, y, a and b. Hence, write the product of the prime factors of the number x so obtained.

Text
Q-00205207
View explanation
Q131

If the HCF of two positive integers a and b is 1, then their LCM is:

Single Answer MCQ
Q-00205232
View explanation
Q132

(2 + √2)^2 is:

Single Answer MCQ
Q-00205234
View explanation
Q133

Assertion (A): For any two natural numbers a and b, the HCF of a and b is a factor of the LCM of a and b. Reason (R): HCF of any two natural numbers divides both the numbers.

Single Answer MCQ
Q-00205245
View explanation
Q134

Prove that √3 is an irrational number.

Text
Q-00205256
View explanation
Q135

The factor tree of a number x is shown. Find the values of x, y, a and b. Hence, write the product of the prime factors of the number x so obtained.

Text
Q-00205257
View explanation
Q136

The value of (HCF × LCM) for the two numbers 3 and 5 is:

Single Answer MCQ
Q-00205280
View explanation
Q137

The number 2ⁿ, where n is a natural number, cannot end with the digit:

Single Answer MCQ
Q-00205282
View explanation
Q138

Assertion (A): The prime numbers which divide 36 also divide 6. Reason (R): Any number which divides p² also divides p. Select the correct option.

Single Answer MCQ
Q-00205298
View explanation
Q139

Prove that √5 is an irrational number.

Text
Q-00205306
View explanation
Q140

State the Fundamental Theorem of Arithmetic and use it to find LCM of 36 and 54.

Text
Q-00205308
View explanation
Q141

The value of (HCF - LCM) for the two numbers 3 and 5 is:

Single Answer MCQ
Q-00205347
View explanation
Q142

The number 3ⁿ, where n is a natural number, cannot end with the digit:

Single Answer MCQ
Q-00205348
View explanation
Q143

Assertion (A): The prime numbers which divide 36 also divide 6. Reason (R): Any number which divides p² also divides p.

Single Answer MCQ
Q-00205354
View explanation
Q144

Prove that √5 is an irrational number.

Text
Q-00205369
View explanation
Q145

State the Fundamental Theorem of Arithmetic and use it to find LCM of 36 and 54.

Text
Q-00205370
View explanation
Q146

The value of (HCF − LCM) for the two numbers 3 and 5 is:

Single Answer MCQ
Q-00205395
View explanation
Q147

If the number aⁿ, where n is a natural number, always ends with digit a, then the possible value of a is:

Single Answer MCQ
Q-00205396
View explanation
Q148

Assertion (A): The prime numbers which divide 36 also divide 6. Reason (R): Any number which divides p² also divides p.

Single Answer MCQ
Q-00205408
View explanation
Q149

Prove that √5 is an irrational number.

Text
Q-00205419
View explanation
Q150

Write the prime factorisation of 36 and 54 and hence find their LCM.

Text
Q-00205421
View explanation
Q151

A prime number has:

Single Answer MCQ
Q-00205691
View explanation
Q152

If p = 2³ × 3² × 5 and q = 2² × 3³, then the LCM of p and q is:

Single Answer MCQ
Q-00205692
View explanation
Q153

3ⁿ, where n is a natural number, cannot end with the digit:

Single Answer MCQ
Q-00205693
View explanation
Q154

Prove that √2 is an irrational number.

Text
Q-00205718
View explanation
Q155

Find which among the following numbers a, b and c is/are composite numbers: a = 7 × 11 × 13 + 13, b = 6 × 5 × 4 + 4, c = 7 × 13 + 6.

Text
Q-00205719
View explanation
Q156

If p = 2³ × 3² × 5 and q = 2² × 3³, then the LCM of p and q is:

Single Answer MCQ
Q-00206152
View explanation
Q157

3ⁿ, where n is a natural number, cannot end with the digit:

Single Answer MCQ
Q-00206153
View explanation
Q158

A prime number has:

Single Answer MCQ
Q-00206154
View explanation
Q159

Prove that √2 is an irrational number.

Text
Q-00206174
View explanation
Q160

Find which among the following numbers a, b and c is/are composite numbers: a = 7 × 11 × 13 + 13, b = 6 × 5 × 4 + 4, c = 7 × 13 + 6.

Text
Q-00206175
View explanation
Q161

If p = 2^3 × 3^2 × 5 and q = 2^2 × 3^3, then the LCM of p and q is:

Single Answer MCQ
Q-00207160
View explanation
Q162

3^n, where n is a natural number, cannot end with the digit:

Single Answer MCQ
Q-00207162
View explanation
Q163

A prime number has:

Single Answer MCQ
Q-00207165
View explanation
Q164

Find which among the following numbers a, b and c is/are composite numbers: a = 7 × 11 × 13 + 13, b = 6 × 5 × 4 + 4, c = 7 × 13 + 6.

Text
Q-00207187
View explanation
Q165

Prove that √2 is an irrational number.

Text
Q-00207189
View explanation
Q166

If HCF (850, 325) is 25, then LCM (850, 325) is:

Single Answer MCQ
Q-00207211
View explanation
Q167

7 × 29 × 23 + 1 is:

Single Answer MCQ
Q-00207227
View explanation
Q168

Assertion (A): 4^n cannot end with the digit zero. Reason (R): Prime factorisation of 4^n is unique.

Single Answer MCQ
Q-00207229
View explanation
Q169

Prove that √5 is an irrational number.

Essay
Q-00207243
View explanation
Q170

7 x 29 x 23 + 1 is:

Single Answer MCQ
Q-00207273
View explanation
Q171

HCF of two consecutive natural numbers is:

Single Answer MCQ
Q-00207278
View explanation
Q172

Assertion (A): 4^n can not end with the digit zero. Reason (R): Prime factorisation of 4^n is unique.

Single Answer MCQ
Q-00207288
View explanation
Q173

Prove that sqrt(5) is an irrational number.

Text
Q-00207298
View explanation
Q174

7 × 11 × 13 + 5 is

Single Answer MCQ
Q-00207324
View explanation
Q175

Find the H.C.F. and L.C.M. of 1530 and 2040.

Text
Q-00207344
View explanation
Q176

Prove that √2 is an irrational number.

Text
Q-00207352
View explanation
Q177

7 × 11 × 13 + 5 is

Single Answer MCQ
Q-00207380
View explanation
Q178

Find the H.C.F. and L.C.M. of 1530 and 2040.

Text
Q-00207400
View explanation
Q179

Prove that √2 is an irrational number.

Text
Q-00207406
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Q180

17 × 11 × 13 + 11 is

Single Answer MCQ
Q-00207441
View explanation
Q181

Find the H.C.F. and L.C.M. of 408 and 312.

Text
Q-00207458
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Q182

Prove that √2 is an irrational number.

Text
Q-00207470
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Q183

The product of the H.C.F. and L.C.M. of two numbers 50 and 20 is

Single Answer MCQ
Q-00207492
View explanation
Q184

Find the smallest 5-digit number exactly divisible by 24 and 36.

Number
Q-00207511
View explanation
Q185

Prove that √2 is an irrational number.

Essay
Q-00207520
View explanation
Q186

Assertion (A): H.C.F. (36m², 18m) = 18m, where m is a prime number. Reason (R): H.C.F. of two numbers is always less than or equal to the smaller number.

Single Answer MCQ
Q-00207563
View explanation
Q187

Prove that 14 - 2√3 is an irrational number, given that √3 is irrational.

Text
Q-00207570
View explanation
Q188

The dimensions of a window are 156 cm × 216 cm. Arjun wants to put grill on the window creating complete squares of maximum size. Determine the side length of the square and hence find the number of squares formed.

Text
Q-00207576
View explanation
Q189

Assertion (A): H.C.F. (36m², 18m) = 18m, where m is a prime number. Reason (R): H.C.F. of two numbers is always less than or equal to the smaller number.

Single Answer MCQ
Q-00207616
View explanation
Q190

Prove that 4 – 2√5 is an irrational number given that √5 is irrational.

Text
Q-00207620
View explanation
Q191

The dimensions of a window are 156 cm × 216 cm. Arjun wants to put grill on the window creating complete squares of maximum size. Determine the side length of the square and hence find the number of squares formed.

Text
Q-00207626
View explanation
Q192

Prove that 2 - 5√3 is an irrational number given that √3 is irrational.

Text
Q-00207669
View explanation
Q193

Assertion (A): H.C.F. (36m^2, 18m) = 18m, where m is a prime number. Reason (R): H.C.F. of two numbers is always less than or equal to the smaller number.

Single Answer MCQ
Q-00207670
View explanation
Q194

The dimensions of a window are 156 cm × 216 cm. Arjun wants to put grill on the window creating complete squares of maximum size. Determine the side length of the square and hence find the number of squares formed.

Text
Q-00207684
View explanation
Q195

Assertion (A): (√3 + √5) is an irrational number. Reason (R): Sum of any two irrational numbers is always irrational.

Single Answer MCQ
Q-00207722
View explanation
Q196

Prove that 2 + 3√5 is an irrational number given that √5 is irrational number.

Text
Q-00207728
View explanation
Q197

If the HCF of 210 and 55 is expressed as 210 × 5 + 55m, then find the value of m.

Text
Q-00207729
View explanation
Q198

Find the greatest number which divides 764 and 1198, leaving remainders 8 and 10 respectively.

Text
Q-00207734
View explanation
Q199

Assertion (A): (√3 + √5) is an irrational number. Reason (R): Sum of any two irrational numbers is always irrational.

Single Answer MCQ
Q-00207778
View explanation
Q200

If the HCF of 210 and 55 is expressed as 210 × 5 + 55m, then find the value of m.

Text
Q-00207780
View explanation
Q201

Prove that 2 + 3√5 is an irrational number given that √5 is irrational.

Text
Q-00207781
View explanation
Q202

A trader has three different types of oils of volume 870 l, 812 l and 638 l. Find the least number of containers of equal size required to store all the oil without getting mixed.

Text
Q-00207786
View explanation
Q203

Assertion (A): (√3 + √5) is an irrational number. Reason (R): Sum of any two irrational numbers is always irrational.

Single Answer MCQ
Q-00207836
View explanation
Q204

If the HCF of 210 and 55 is expressed as 210 × 5 + 55m, then find the value of m.

Number
Q-00207841
View explanation
Q205

Prove that 2 + 3√5 is an irrational number given that √5 is an irrational number.

Text
Q-00207843
View explanation
Q206

Find the greatest number less than 10,000 which is exactly divisible by 48, 60 and 65.

Number
Q-00207854
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Q207

Which of the following is a rational number between √3 and √5?

Single Answer MCQ
Q-00208111
View explanation
Q208

If HCF(98, 28) = m and LCM(98, 28) = n, then the value of n − 7m is:

Single Answer MCQ
Q-00208112
View explanation
Q209

The greatest number which divides 70 and 125, leaving remainders 5 and 8 respectively, is:

Single Answer MCQ
Q-00208114
View explanation
Q210

Three sets of Physics, Chemistry and Mathematics books have to be stacked in such a way that all the books are stored subject-wise and the height of each stack is the same. The number of Physics books is 144, the number of Chemistry books is 180 and the number of Mathematics books is 192. Assuming that the books are of same thickness, determine the number of stacks of Physics, Chemistry and Mathematics books.

Text
Q-00208129
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Real Numbers Practice Worksheets

Download and practice Real Numbers worksheets to improve problem-solving accuracy and speed for CBSE Class 10 Mathematics exams.

Real Numbers - Practice Worksheet

This worksheet covers essential long-answer questions to help you build confidence in Real Numbers from Mathematic for Class 10 (Mathematics).

Practice

Questions

1

Explain Euclid’s Division Algorithm and provide an example to illustrate its application in finding the HCF of two integers.

Euclid’s Division Algorithm states that for any two positive integers a and b, there exist unique integers q (the quotient) and r (the remainder) such that a = bq + r, where 0 ≤ r < b. For example, to find the HCF of 48 and 18, we divide 48 by 18, yielding 48 = 18 × 2 + 12. Then, apply the algorithm again: 18 = 12 × 1 + 6. Finally, 12 = 6 × 2 + 0, so HCF(48, 18) = 6. This algorithm is effective due to its recursive nature.

2

Define the Fundamental Theorem of Arithmetic and demonstrate its significance with an example.

The Fundamental Theorem of Arithmetic states that every composite number can be expressed as a product of primes in a unique way, excluding the order of factors. For instance, consider the number 30. Its prime factorization is 30 = 2 × 3 × 5. No matter how we group or order these primes, we arrive at the same product. This theorem is essential for understanding number theory as it allows for unique prime factorization.

3

Prove that √2 is an irrational number using the method of contradiction.

Assume √2 is rational, meaning it can be expressed as a/b, where a and b are coprime integers. Squaring both sides yields 2 = a²/b², leading to a² = 2b². This shows that a² is even, implying a must also be even. Thus, we write a = 2k for some integer k, giving 2k² = b². This indicates b² is even, consequently b is even. Since both a and b have 2 as a common factor, this contradicts our assumption that they are coprime. Hence, √2 is irrational.

4

How do you determine if the decimal expansion of a rational number is terminating or non-terminating? Provide an example.

To check if a rational number p/q has a terminating decimal, examine the prime factorization of the denominator, q, after simplifying p/q. If the only primes in q are 2 or 5, the decimal is terminating. For example, for 3/8, the factorization of 8 is 2³, which consists solely of 2s. Thus, 3/8 has a terminating decimal (0.375). Contrastingly, for 1/3 (where q = 3), the decimal is non-terminating (0.333...).

5

Find the HCF and LCM of the numbers 56 and 72 using the prime factorization method.

For 56, the prime factorization is 2³ × 7, while for 72, it is 2³ × 3². To find the HCF, take the lowest power of each common prime factor: HCF = 2³ = 8. For the LCM, take the highest power of all primes appearing: LCM = 2³ × 3² × 7 = 8 × 9 × 7 = 504. Thus, HCF(56, 72) = 8 and LCM(56, 72) = 504.

6

Discuss how to express a number as a product of its prime factors. Provide an example with a solution.

To express a number as a product of prime factors, continuously divide the number by the smallest prime number until the quotient is 1. For example, for the number 84: dividing by 2 gives 42; dividing 42 by 2 gives 21; dividing by 3 yields 7, a prime itself. Therefore, 84 = 2 × 2 × 3 × 7 or 84 = 2² × 3 × 7. This prime factorization shows each factor's power uniquely.

7

Explain why the product of a non-zero rational number and an irrational number is always irrational.

Let r be a non-zero rational number and s an irrational number. Assume the product rs is rational. This means rs could be expressed as p/q, where p and q are integers. Therefore, s = (p/q) / r. Since r is non-zero, s would be rational if expressed this way, contradicting the fact that s is irrational. Hence, the product rs must also be irrational.

8

Demonstrate using an example that the sum of a rational and an irrational number is irrational.

Consider the rational number 3 (which can be expressed as 3/1) and the irrational number √2. If their sum (3 + √2) were rational, we could express it as a/b for integers a and b. Rearranging gives √2 = (a/b) - 3, which means √2 is rational. This is a contradiction since √2 is known to be irrational. Thus, 3 + √2 is irrational.

9

What are the necessary conditions for a number to be considered irrational? Provide examples.

A number is considered irrational if it cannot be expressed in the form p/q, where p and q are integers and q ≠ 0. Common examples include √2, π, and e. Unlike rational numbers which can be expressed as fractions, these numbers have non-terminating and non-repeating decimal expansions, making them irrational.

Real Numbers - Mastery Worksheet

This worksheet challenges you with deeper, multi-concept long-answer questions from Real Numbers to prepare for higher-weightage questions in Class 10.

Mastery

Questions

1

Compare and contrast the concepts of rational and irrational numbers, providing examples and implications for their use in real-world scenarios.

Rational numbers can be expressed as the ratio of two integers (e.g., 1/2, 3) while irrational numbers cannot be expressed in this form (e.g., √2, π). Consequently, rational numbers are countable, whereas irrational numbers are uncountable, leading to different applications in mathematics and real-life calculations.

2

Using Euclid's division algorithm, find the HCF of 96 and 404 and verify your answer using the fundamental theorem of arithmetic.

Euclid's algorithm reveals HCF(96, 404) = 4. By prime factorization: 96 = 2^5 × 3, 404 = 2^2 × 101, hence HCF = 2^2 = 4. This confirms the HCF found.

3

Prove that √3 is irrational using the contradiction method and the fundamental theorem of arithmetic.

Assume √3 = a/b (where a and b are coprime integers). Then 3b² = a² leads to a contradiction as both a and b would be divisible by 3. Thus, √3 cannot be expressed as a ratio of integers, proving it is irrational.

4

Explain how the fundamental theorem of arithmetic can be used to determine if a rational number has a terminating decimal expansion.

A rational number's decimal is terminating if and only if the prime factorization of its denominator includes only 2 and/or 5. For instance, 1/8 = 0.125 (terminating), but 1/3 = 0.333... (non-terminating) because 3 is not 2 or 5.

5

Find and explain the relationship between the LCM and HCF of the numbers 12, 15, and 21.

HCF(12, 15, 21) = 3 and LCM(12, 15, 21) = 60. The relationship is shown as HCF × LCM = product of the numbers (3 × 60 = 180 = 12 × 15 = 180).

6

Prove that the statement 'The sum of a rational and an irrational number is irrational' is true.

Assume the contrary, that r + x is rational where r is rational and x is irrational. Rearranging gives x = (r + x) - r, making x expressible as a rational number, contradicting the assumption that x is irrational.

7

Using prime factorization, find the LCM and HCF of 26 and 91 and verify that LCM*HCF equals the product of the two numbers.

26 = 2 × 13, 91 = 7 × 13. Hence, HCF = 13, LCM = 2 × 7 × 13 = 182. Verification: LCM × HCF = 182 × 13 = 2366, which equals 26 × 91.

8

Explain why the number 4ⁿ cannot end with the digit zero for any natural number n.

4ⁿ = 2^(2n). Since this only includes the prime factor 2, and lacks the factor 5 needed for ending in zero, it cannot yield a product that ends in zero.

9

Find and illustrate the prime factorization of 5005 and explain its relevance to understanding the nature of composite numbers.

5005 = 5 × 7 × 11 × 13. Each prime factor represents distinct building blocks of composite numbers. Understanding this composition helps in factorization and divisibility rules.

10

How do the properties of real numbers discussed in this chapter apply to simplifications involving radicals? Illustrate with examples.

Properties such as √(a/b) = √a/√b help in simplifying expressions. For example, √(8/2) = √8/√2 = √4 = 2 illustrates how radical simplifications can yield rational results.

Real Numbers - Challenge Worksheet

The final worksheet presents challenging long-answer questions that test your depth of understanding and exam-readiness for Real Numbers in Class 10.

Challenge

Questions

1

Evaluate the implications of the Fundamental Theorem of Arithmetic on the uniqueness of prime factorization in the context of composite numbers. How does this theorem assist in numerical cryptography?

Discuss numerical uniqueness and how prime factorization aids in securing digital communications.

2

Analyze the correlation between Euclid’s Division Algorithm and the determination of the Highest Common Factor (HCF) among three composite numbers. Provide real-world examples of its application.

Explore efficiency in computational methods applied in various fields, such as engineering or computer science.

3

Discuss the characteristics that distinguish terminating and non-terminating decimal expansions in rational numbers. Include examples of each and explain their significance.

Examine the link to prime factorization of denominators and explain implications in mathematical representation.

4

Evaluate the proof of irrationality for √5. What implications does this have on the broader understanding of irrational numbers?

Consider the impact of proofs on mathematical theory and how they enhance logical reasoning.

5

How do the properties of irrational numbers assist in identifying the boundaries of the real number system?

Assess how irrational numbers contribute to the completeness of real numbers and provide relevant examples.

6

Investigate the application of prime factorization in solving real-world problems, such as determining the optimal packaging of products.

Discuss how HCF and LCM can simplify logistics and inventory management.

7

Compare and contrast the concepts of HCF and LCM. How can understanding both improve problem-solving strategies in complex mathematical scenarios?

Illustrate with examples involving fractions and their simplifications.

8

Explore the significance of irrational numbers in geometric contexts. Provide examples showing their application in calculating areas or lengths.

Analyze irrational numbers' utility in constructing accurate models in design and architecture.

9

Evaluate the effects of irrational numbers on polynomial equations. Include examples where irrationals emerge as roots and identify their relevance to real solutions.

Discuss notions of roots in polynomial equations and how they connect to the fundamental concept of real numbers.

10

Given a set of rational and irrational numbers, analyze the operations (addition, multiplication) and justify your rationale for the outcomes observed.

Discuss number theory implications for operations with mixed types of numbers.

Real Numbers Formula Sheet

Use this Class 10 Mathematics Real Numbers Formula Sheet for quick revision before school exams and CBSE exams. It brings together the important formulas, key concepts, and worked examples in one place so students can revise faster and download a printable PDF for offline study.

Important Formulas

1

HCF(a, b) × LCM(a, b) = a × b

HCF is the Highest Common Factor and LCM is the Least Common Multiple of integers 'a' and 'b'. This relationship helps in computing either HCF or LCM if the other is known.

2

p/q is terminating if prime factors of q are only 2 and/or 5.

For a rational number to have a terminating decimal expansion, its denominator (when expressed in simplest form) must contain only the prime factors 2 and 5.

3

a² + b² = c² (Pythagorean Theorem)

In a right triangle, the square of the hypotenuse (c) equals the sum of the squares of the other two sides (a and b).

4

Euclid's Division Algorithm: a = bq + r (0 ≤ r < b)

'a' is the dividend, 'b' is the divisor, 'q' is the quotient, and 'r' is the remainder. This helps to compute the HCF of two integers.

5

If p is a prime and p | a², then p | a.

This theorem states that if a prime number divides the square of an integer, it must also divide the integer itself.

6

Number of primes ≤ n: π(n) ≈ n / log(n)

This approximation describes the distribution of prime numbers up to 'n'. Useful for understanding the density of primes.

7

Prime factorization of a composite number x: x = p₁^e₁ × p₂^e₂ × ... × pₖ^eₖ

'p₁, p₂,..., pₖ' are prime factors and 'e₁, e₂,..., eₖ' are their respective powers. This expresses 'x' uniquely in terms of its prime factors.

8

Square root of a prime: √p is irrational.

The square root of any prime number 'p' cannot be expressed as a fraction of integers, confirming its irrational nature.

9

Irrational numbers: cannot be expressed as p/q (where p, q are integers and q ≠ 0).

Examples include numbers like √2, π, which cannot be precisely expressed as ratios of two integers.

10

Decimal expansion of a rational number is either terminating or repeating.

This emphasizes that rationals have a predictable decimal structure, aiding in classification.

Worked Examples

1

HCF(96, 404) = 4

The calculation of the HCF using prime factorization shows common prime factors and their smallest powers.

2

LCM(6, 20) = 60

The LCM is determined by taking the highest power of all prime factors in the numbers involved.

3

√2 is irrational.

The proof by contradiction shows that assuming √2 is rational leads to an inconsistency.

4

√3 is irrational.

Similar to √2, √3 cannot be expressed as a ratio of integers, establishing its irrationality.

5

2^1 × 3^1 = 6 (for HCF)

For numbers 6 and 72, this illustrates the process of finding the HCF by locating common prime factors.

6

2^3 × 3^2 × 5^1 = 360 (for LCM)

For numbers 6, 72, and 120, this demonstrates calculating the LCM using prime factors.

7

Euclid's Algorithm: GCD(48, 18) = 6

Applying Euclid's division method yields the Greatest Common Divisor of the two numbers.

8

4² = 16 (not ending in zero)

This indicates that certain forms of numbers, such as powers of 4, do not yield multiples of 10.

9

5 - √3 is irrational.

Assuming the result is rational shows logical inconsistencies, confirming the irrationality of this expression.

10

HCF(p, q, r) × LCM(p, q, r) ≠ p × q × r

Highlighting that the product of three numbers does not equal the product of their HCF and LCM.

Explore More Real Numbers Resources

Explore more chapter resources to strengthen your understanding and prepare for exams.

Real Numbers Frequently Asked Questions

Explore the chapter on Real Numbers in Class 10 Mathematics covering concepts like the Fundamental Theorem of Arithmetic and irrational numbers. Ideal for enhancing understanding and performance.

The Fundamental Theorem of Arithmetic states that every composite number can be expressed as a product of primes in a unique way, apart from the order of the factors. This theorem is foundational in number theory and ensures the unique factorization of integers.
Euclid's Division Algorithm states that for any two positive integers 'a' and 'b', there exist unique integers 'q' and 'r' such that a = bq + r, where 0 ≤ r < b. This method is primarily used to find the Highest Common Factor (HCF) of integers.
Irrational numbers, like √2 and π, cannot be expressed as a simple fraction, providing insight into the properties of numbers beyond whole numbers and fractions. They are significant in mathematics for their appearances in various contexts like geometry and calculus.
Yes, every real number is either rational, which can be written as a fraction, or irrational, which cannot. This classification helps in understanding the number system and properties related to mathematical operations involving real numbers.
An example of its application is in finding the HCF and LCM of two numbers. By expressing numbers in terms of their prime factors, we can easily identify common factors for HCF and combined prime factors for LCM.
To prove √2 is irrational, assume it can be expressed as a/b (with a and b in lowest terms). By manipulating the equation, we show that both a and b must be even, leading to a contradiction as they can't have a common factor other than 1.
Irrational numbers include numbers like √2, π, and e. These cannot be expressed as fractions of integers and have non-repeating, non-terminating decimal expansions, distinguishing them from rational numbers.
A terminating decimal has a finite number of digits after the decimal point (like 0.75) while a non-terminating decimal continues infinitely without repeating (like 1/3 = 0.333…). Their classification helps in identifying rational numbers.
Rational numbers can be accurately located on the number line since they correspond to exact points, while irrational numbers can be approximated and are represented by locations that do not coincide with simple fractions.
The relationship states that for any two integers 'a' and 'b', the product of their HCF and LCM is equal to the product of the numbers themselves: HCF(a, b) × LCM(a, b) = a × b.
An example is to find HCF(96, 404) using the prime factorization method. It involves factorizing both numbers and selecting the smallest powers of all common prime factors to compute HCF.
To express a number as a product of primes, we factorize the number by dividing it by the smallest prime until reaching 1, documenting the prime factors along the way to achieve the number's prime factorization.
Strategies include using number lines to visualize placements, comparing rational numbers as fractions, demonstrating irrational numbers through decimal expansions, and solving real-world problems where these concepts apply.
A decimal expansion of a rational number is terminating if the denominator of its simplest form has no prime factors other than 2 and 5. If additional primes exist, the decimal expansion will be non-terminating.
Prime numbers are critical in the theorem as they serve as the building blocks for all composite numbers. Each composite can be uniquely expressed as a multiplication of prime factors, forming the essence of number theory.
A real-life example includes dividing resources evenly. If 20 cookies need to be shared among 7 friends, the algorithm can help determine how many cookies each person gets and how many remain.
The method involves repeated division of the number by the smallest possible prime until only 1 remains. Each prime used in the division will be part of the final prime factorization.
Unique prime factorization is necessary as it allows for a systematic way to study integers and their properties, ensuring consistency across mathematical operations such as finding HCF and LCM.
Understanding real numbers equips students with essential math skills applicable in various fields such as science, engineering, finance, and technology, where numerical reasoning and calculations are fundamental.
Common misconceptions include assuming all decimal numbers are rational or misunderstanding how irrational numbers cannot be neatly expressed as fractions, leading to confusion in their properties.
The number π is a crucial irrational number representing the ratio of a circle's circumference to its diameter. Its properties and applications are fundamental in geometry and trigonometry.
Irrational numbers introduce complexities in calculations, especially in approximations. When used with rational numbers, they always create results that are also non-terminating, affecting precision in problem-solving.
The study of Real Numbers establishes a critical foundation for topics in higher mathematics, including algebra, calculus, and analysis, where understanding both rational and irrational numbers is essential.
Exercises can include problems on finding HCF and LCM, expressing numbers as products of primes, identifying rational and irrational numbers from given sets, and applying these concepts in practical scenarios.
A rational number is defined as any number that can be expressed in the form p/q, where p and q are integers and q is not zero. This definition includes integers, fractions, and terminating decimals.

Real Numbers PDF Downloads

Download worksheets, revision guides, formula sheets, and the official textbook PDF for Real Numbers.

Real Numbers Official Textbook PDF

Download the official NCERT/CBSE textbook PDF for Class 10 Mathematics.

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Real Numbers Revision Guide

Use this one-page guide to revise the most important ideas from Real Numbers.

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Real Numbers Formula Sheet

Download the Real Numbers formula sheet PDF with important formulas, worked examples, and quick revision support for exam preparation.

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Real Numbers Practice Worksheet

Solve basic and application-based questions from Real Numbers.

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Real Numbers Mastery Worksheet

Work through mixed Real Numbers questions to improve accuracy and speed.

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Real Numbers Challenge Worksheet

Try harder Real Numbers questions that test deeper understanding.

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Real Numbers Question Bank

Download important questions and exam-style prompts from Real Numbers.

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Real Numbers Flashcards

Revise key terms and definitions from Real Numbers with interactive flashcards. Quick recall practice for CBSE Class 10 Mathematics.

These flash cards cover important concepts from Real Numbers in Mathematics for Class 10 (Mathematics).

1/20

What are real numbers?

1/20

Real numbers include all rational and irrational numbers. They can be found on the number line.

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2/20

Define rational numbers.

2/20

Rational numbers are numbers that can be expressed as p/q, where p and q are integers and q ≠ 0.

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3/20

What are irrational numbers?

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3/20

Irrational numbers cannot be expressed as a fraction of two integers. Examples include √2 and π.

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4/20

State the Fundamental Theorem of Arithmetic.

4/20

Every composite number can be expressed as a product of its prime factors in a unique way, except for the order of the factors.

5/20

What is Euclid's division algorithm?

5/20

It states that for any two positive integers a and b, there exist unique integers q and r such that a = bq + r, where 0 ≤ r < b.

6/20

Factor 60 into primes.

6/20

60 = 2² × 3 × 5.

7/20

Why is prime factorization unique?

7/20

Each composite number can be factorized into primes in only one way, except for the order of the factors.

8/20

What is the relation between HCF and LCM?

8/20

HCF(a, b) × LCM(a, b) = a × b for any two integers a and b.

9/20

When does a rational number have terminating decimal expansion?

9/20

A rational number p/q has a terminating decimal if the prime factorization of q (in lowest terms) contains only 2s and/or 5s.

10/20

How do we prove √2 is irrational?

10/20

Assume √2 = p/q in simplest form. Squaring leads to a contradiction that p and q share a common factor.

11/20

List examples of irrational numbers.

11/20

Examples include √2, √3, π, and e.

12/20

What is the sum of a rational and an irrational number?

12/20

The sum is always irrational.

13/20

What are non-terminating repeating decimals?

13/20

These are fractions whose decimal expansion repeats indefinitely, like 1/3 = 0.3333...

14/20

How to find HCF using prime factorization?

14/20

List prime factors, take the lowest power for common factors.

15/20

Find LCM using prime factorization.

15/20

Take the highest power of all prime factors involved.

16/20

What types of decimal expansions exist?

16/20

Decimal expansions are either terminating or non-terminating (repeating or non-repeating).

17/20

What common error is made in identifying irrationals?

17/20

Assuming that sums or products of rationals result in rational numbers when involving irrationals.

18/20

What is proof by contradiction?

18/20

Assuming the opposite of what you want to prove leads to a contradiction, thereby proving the original statement.

19/20

Define composite numbers.

19/20

Composite numbers have more than two distinct positive divisors.

20/20

Find LCM of 4 and 5.

20/20

LCM of 4 and 5 is 20, as they have no common factors.

Practice Real Numbers with Interactive Duels

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Master Real Numbers via Live Academic Duels

Challenge your classmates or test your individual retention on the core concepts of CBSE Class 10 Mathematics (Mathematics). Compete in speed-recall question rounds matched explicitly to the latest syllabus milestones for Real Numbers.

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