# Number - Facts and Type of number

**Numeral **: In Hindu Arabic system, we use ten symbols 0, 1, 2, 3, 4, 5, 6, 7, 8, 9
called digits to represent any number. And a group of digits, denoting a number is called a numeral.

## TYPES OF NUMBERS

1.Natural Numbers : Counting numbers 1, 2, 3, 4, 5,..... are called natural
numbers.

2.Whole Numbers : All counting numbers together with zero form the set of whole
numbers. Thus,

- 0 is the only whole number which is not a natural number.
- Every natural number is a whole number.

3.Integers : All natural numbers, 0 and negatives of counting numbers i.e.,
{..., - 3 , - 2 , - 1 , 0, 1, 2, 3, ...,} together form the set of integers.

- Positive Integers : {1, 2, 3, 4, ..., ...} is the set of all positive integers.
- Negative Integers : {- 1, - 2, - 3,.., ..} is the set of all negative integers.
- Non-Positive and Non-Negative Integers : 0 is neither positive nor
negative. So, {0, 1, 2, 3, ..., ...} represents the set of non-negative integers, while
{0, - 1 , - 2 , - 3 ,.., ..} represents the set of non-positive integers.

4. Even Numbers : A number divisible by 2 is called an even number, e.g., 2, 4, 6, 8,
10, etc.

5. Odd Numbers : A number not divisible by 2 is called an odd number. e.g., 1, 3, 5, 7,
9, 11, etc.

6. Prime Numbers : A number greater than 1 is called a prime number, if it has exactly