Classification of numbers:-
Description of different types of
numbers:-
Natural number:- Natural numbers are those used for counting (as “there
are four coins on the table.”) and ordering (as “this is the fifth
largest city in the country.”) Ex.:- 1, 2, 3, 4, 5 etc.
Real number:-
A real number is a value of a continuous quantity that can represent a distance
along a line. Ex:- 0, 1, √3, -7 etc.
Rational number:- A rational number is any number that can be
expressed as the quotient or fraction p/q of two integers , a numerator p and
a non-zero denominator q. Moreover any
repeating or terminating decimal represents a rational number. Ex:- 0, 1, 3/4, -7/5
etc.
Irrational number:- An irrational number is a number that cannot be
expressed as a fraction p/q for any integer p and q. Irrational number has
decimal expansions neither terminate nor become periodic. Ex:- π(=3.14159…),
√3, √21 etc.
Whole number:- The whole numbers are the natural numbers together
with zero.
Integer:- An integer is a whole number that can be positive
negative or zero. Ex:- 0, 1, -2 etc.
BLOCK DIAGRAM OF CLASSIFICATION OF NUMBERS
Fractional numbers:- A fraction represents a part of a whole
consisting of a numerator and a denominator. Ex:- ½, -3/4, 21/11 etc.
Proper fraction:-A proper fraction is a fraction where the numerator
(the top number of a fraction) is less than the denominator (the bottom number
of a fraction). Ex:- ½, ¼, ¾ etc.
Improper fraction:- An improper fraction is a fraction where the
numerator is greater than the denominator. Ex:- 21/11, 49/36 etc.
Negative number:- A negative number is a real number that is less
than zero. Ex:- -√5, -3, -5/8 etc.
Positive number:- A positive number is a real number that is greater
than zero. Ex:- 11, 17/23, √3 etc.
Even number:- An even number is an integer which is “evenly
divisible” by 2. This means that if the integer is divided by 2, it yields no
remainder. Ex:-0, 2, 4, 6, 14 etc.
*Zero is an even number
because zero divided by two equals zero, which is an integer.
Odd number:- An odd number is an integer which is not a multiple
of 2 i.e. when divided by two the integer leaves a remainder. Ex:- 3, 13, 29
etc.
Prime number:- A prime number is a whole number greater than 1
whose only factors are 1 and itself. Ex:- 2, 3, 5, 37, 97 etc.
*2 is the only even number
which is a prime number.
Composite number:- A composite number is an integer greater than 1
which has factors other than 1 and itself.
*1 is neither a prime nor a
composite number.
Co-prime number:- Two integers a and b are said to be relatively
prime or co-prime if the only positive number that divides both of them is 1.
This is equivalent to the greatest common divisor (g.c.d) being 1.
Perfect number:- A perfect number is a positive integer that is equal
to the sum of its positive divisors excluding the number itself
(also known as its aliquot sum).
(also known as its aliquot sum).
Ex:- 6, 28, 496 etc. Proper
divisors of 6 are 1, 2, 3. Aliquot sum of 6 is 1 + 2 + 3 = 6 which is equal to the
number itself.
Complex number:- A complex number is a number that can be expressed
in the form of a + bi, where a and b are real numbers and ’i’ is an imaginary
number.
Ex:- √(-1), √(-43), √(-97)
etc.
The video given below describes very lively about the classification of numbers.




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