- Books Name
- CBSE Class 6 Mathematics Book

- Publication
- Param Publication

- Course
- CBSE Class 6

- Subject
- Mathmatics

**Types of Numbers**

**(a) Even Number :** A number which is exactly divisible by 2 is called an even number.

Examples of even numbers are : 0, 12, 34, 56, 78,....

**(b) Odd Number : **A number which is not exactly divisible by 2 is called an odd number.

Examples of odd numbers are : 1, 13, 15, 25, 29,....

**(c) Prime Numbers :** A natural number greater than 1, which has no factors except 1 and itself is called a prime number.

Examples of prime numbers are : 2, 3, 5, 11, 13, 17, ...

** (d) Composite Numbers : **A number is composite if it has at least one factor other than 1 and itself.

Examples of composite numbers are : 4, 6, 8, 9,10, 12, 14,...

**Note :**

(i) 1 is neither prime nor composite.

(ii) Every natural number except 1 is, either a prime number or a composite number.

(iii) 2 is the only prime number which is even. All other prime numbers are odd.

**(f) Perfect Numbers :** If the sum of all the factors of a number is twice the number, then number is called a perfect number. For example, 6 is a perfect number since the factors of 6 are 1, 2,3, 6 and their sum 1 + 2 + 3 + 6 = 2 × 6.

**(g) Coprime Numbers :** Two numbers are said to be coprime if they do not have a common factor other than 1.

Examples of coprime numbers are : (8, 15); (5, 9); (2, 11)

**Note :**

(i) Two prime numbers are always coprime.

(ii) Two coprime numbers need not be both prime numbers.