Various Types of Numbers

In various types of numbers we will learn about even numbers, odd numbers, prime numbers, composite numbers, co-prime numbers and twin prime numbers along with the example:

Even Numbers

A whole number exactly divisible by 2 is called even numbers.

For example:

2, 4, 6, 8, 10, 12, 14, 16……………………..are even number. Or a number having 0, 2, 4, 6, 8 at its units place is called an even number.

246, 1894, 5468, 100 are even number.

Any two even numbers which differ from one another by 2 are called consecutive even number.

Odd Numbers

A whole number which is not exactly divisible by 2 is called an odd number.

For example:

3, 5, 7, 9, 11, 13, 15, are odd number.

Or a number having 1, 3, 5, 7 and 9 at its units place is called an odd number.

Prime Numbers

Number s which have only two factors namely 1 and the number itself are called prime numbers.

For example:

2, 3, 5, 7, 11, 19, 37 etc are prime numbers.

Composite Numbers

Numbers having more than two factors are called as composite numbers.

For example:

4, 6, 8, 10 etc are composite numbers.

Notes:

(a) 1 is neither prime nor composite.

(b) 2 is the lowest and the only even prime number.

(c) 9 is the lowest odd composite number.

Co-prime Numbers

Two numbers are said to be co-prime if they do not have a common factor other than 1 or two numbers whose HCF is 1 called co-prime numbers.

Co-prime numbers needs not be prime numbers.

For example:

(i) 7 and 10 are co-prime.

(ii) 15 and 17 are co-prime.

Twin Prime Numbers

Twin prime numbers are the two prime numbers whose difference is 2.

For example:

(i) 3 and 5

(ii) 17 and 19

(iii) 41 and 43

(iv) 29 and 31

(v) 71 and 73.