# Arithmetic Course/Types of Number/Natural Number

## Natural Number[edit]

Natural Number is a set of all digits from 0 to 9

- N = {1,2,3,4,5,6,7,8,9}

### Even Number[edit]

Natural Number divisible by two is called Even Number

- 2N = {2,4,6,8}

### Odd Number[edit]

Natural Number not divisible by two is called Odd Number

- 2N + 1 = {1,3,5,7,9}

## Prime Number[edit]

prime number"p"" is the number that have 4 divisors [p,-p,1,-1]

- p=[2,3,5,7,9,11,.................]