Real numbers class 10 important questions with solutions – Real numbers class 10

Real Numbers are a combination of rational and irrational Numbers, forming a continuous set on the number line.

Real numbers are a combination of rational and irrational numbers, forming a continuous set on the number line.

Real numbers are a combination of rational and irrational numbers, forming a continuous set on the number line.

Introduction to Real Numbers – real numbers class 10

Real Numbers are a fundamental concept in mathematics, particularly emphasized in real numbers class 10 curriculum. These numbers encompass a vast range, including rational numbers, irrational numbers, and whole numbers, forming the building blocks of mathematical operations.

real numbers class 10

In class 10 real numbers studies, students delve into the intricacies of number systems, exploring the properties and relationships among different types of real numbers. Understanding real numbers is essential for various mathematical applications, from basic arithmetic to advanced algebraic equations.

The classification of numbers into real numbers provides a comprehensive framework for mathematical reasoning and problem-solving. Students learn to manipulate real numbers through addition, subtraction, multiplication, and division, gaining proficiency in numerical operations.

Moreover, real numbers extend beyond simple numerical values; they are essential in representing quantities in scientific notation, equations in geometry, and calculations in physics and engineering.

Types of Real Numbers – real numbers class 10

• Natural numbers: ( 1, 2, 3, \ldots )
• Whole numbers: ( 0, 1, 2, 3, \ldots )
• Integers: \( \ldots, -3, -2, -1, 0, 1, 2, 3, \ldots \)
• Rational numbers: Numbers that can be expressed as a ratio of two integers, such as \( {1}/{2} \) or ( -\frac{3}/{4} ).
• Irrational numbers: Numbers that cannot be expressed as a ratio of two integers, such as ( √{2} ) or ( π\pi ).

Rational numbers are those that can be expressed as fractions (p/q) or ratios of integers, such as 1/2, -3/4, or 5.

Irrational numbers, like √2 or π, cannot be expressed as fractions and have non-repeating, non-terminating decimal representations.

Real numbers are used to represent quantities in various mathematical and scientific contexts, providing a complete and unified number system.

real numbers.

2. Properties of Real Numbers: – real numbers class 10

• Closure Property: Real numbers are closed under addition, subtraction, multiplication, and division. For any two real numbers a and b, their sum, difference, product, and quotient (when b is not zero) are also real numbers.
•    Commutative Property: Addition and multiplication of real numbers are commutative, meaning changing the order of numbers does not change the result (a + b = b + a, and ab = ba).
•    Associative Property: Addition and multiplication are associative, meaning the grouping of numbers does not affect the result ((a + b) + c = a + (b + c), and (ab)c = a(bc)).
•    Distributive Property: Multiplication distributes over addition and subtraction (a(b + c) = ab + ac, and a(b – c) = ab – ac).
•    Identity Elements: Zero is the additive identity (a + 0 = a) and one is the multiplicative identity (a × 1 = a).
•    Inverse Elements: Every real number a has an additive inverse (-a) such that a + (-a) = 0, and every non-zero real number has a multiplicative inverse (1/a) such that a × (1/a) = 1.

3. Classification of Real Numbers: – real numbers class 10

   Rational Numbers: These are numbers that can be expressed as fractions or ratios of integers. They include integers, terminating decimals, and repeating decimals (like 0.25 or 3/7).

   Irrational Numbers: Numbers that cannot be expressed as fractions and have non-repeating, non-terminating decimal expansions. Examples include √2, π, and e.
   Together, rational and irrational numbers form the set of real numbers, covering all possible values on the number line.

4. Important Topics in Real Numbers: – real numbers class 10

• Decimal Representation: Rational numbers can be represented as terminating or repeating decimals. For example, 3/4 = 0.75 and 1/3 = 0.333…
•    -Converting Recurring Decimals to Fractions: Techniques like writing x = 0.333… and multiplying by an appropriate power of 10 to eliminate the repeating part can be used to convert recurring decimals to fractions.
•    Surds: These are expressions involving square roots of non-perfect squares, such as √2, √5, etc. Surds have properties related to simplification and manipulation.
•    Laws of Exponents: Rules governing the manipulation of exponents, including multiplication, division, power of a power, and negative exponents, applied to real numbers.

5. Density of Real Numbers

Between any two real numbers, there exists an infinite number of other real numbers. This property is known as the density of real numbers.

6. Decimal Representation of Real Numbers

Real numbers can be represented in decimal form, either terminating (like ( 0.5 )) or non-terminating and non-repeating (like ( pi ) π).

Qns: Prove that √2 is an irrational number?

To prove that √2 is an irrational number, we can use proof by contradiction.

Assume, for the sake of contradiction, that √2 is a rational number. This means it can be expressed as a ratio of two integers in its simplest form, such as ( frac{p}{q} ), where ( p ) and ( q ) are integers with no common factors other than 1, and ( q ) is not zero.

So, we have:

√{2} = {p}/{q}

Squaring both sides of the equation:

2 = p^2}/{q^2}

Multiplying both sides by ( q^2 ):

[ 2q^2 = p^2 ]

This implies that ( p^2 ) is even because it is equal to ( 2q^2 ). If ( p^2 ) is even, then ( p ) must also be even because the square of an odd number is odd. So, we can write ( p ) as ( 2k ) for some integer ( k ).

Substituting ( p = 2k ) back into the equation:

[ 2q^2 = (2k)^2 ]
[ 2q^2 = 4k^2 ]
[ q^2 = 2k^2 ]

This shows that ( q^2 ) is also even, which means ( q ) must be even as well.

However, this contradicts our initial assumption that ( p ) and ( q ) have no common factors other than 1, because if both ( p ) and ( q ) are even, then they have a common factor of 2.

Since our assumption leads to a contradiction, we conclude that √2 cannot be expressed as a rational number. Therefore, √2 is an irrational number.

7. Real numbers class 10 – Questions and Answers: