**Number System**

Number System forms a basis of many other topics in mathematics. To understand Number System is very essential for solving various types of problems in mathematics. It teach you to distinguish various types of Number. Let us begin by understanding various types of number.

**Natural Number:**

All the counting numbers are called Natural Number. There are infinitely many natural numbers.

**Example: 1,2,3,4,5,6…..etc.**

These natural number may be of following type:

#### 1. Even numbers:

The numbers which divisible by 2 are called even number.

**Example: 2,4,6,8,10,12**

#### 2. Odd number:

The number which leaves a remainder 1 when divided by 2 are called odd numbers.

**Example: 1,3,5,7…..**

#### 3. Prime Numbers:

If a number is not divisible by any other number except 1 and itself, it is called a prime number.

**Example: 2,3,5,7,11….**

#### 4. Composite number:

Numbers which are divisible by other numbers along with 1 and itself are called composite numbers.

**Example: 4,6,8,9…**

#### Note: The number 1 is neither prime nor composite.

**Whole Numbers:**

Natural number along with 0 are called Whole numbers.

**Example: 0,1,2,3…**

**Integers:**

All counting numbers and their negative along with zero are called integers.

**Example: ….-4, -3, -2, -1, 0, 1, 2, 3**

**Rational Numbers:**

Any number which can be expressed in form of p/q are called rational number. where p & q are integers.

**Example: -2/5, 3, -4 etc**

**Irrational Numbers:**

Numbers which are represented by noon terminating and non-recurring decimal are called irrational Numbers

**Example:**

π = 3.1415926535897932384…

√2 = 1.14121356230951…..

**Real Numbers:**

The real numbers are the set of numbers containing all of the rational numbers and all of the irrational numbers. The real numbers are “all the numbers” on the number line.

**The Complex Numbers**

The complex numbers are the set {a+bi | a and b are real numbers}, where i is the imaginary unit.

The complex numbers include the set of real numbers. The real numbers, in the complex system, are written in the form a+0i=a. a real number.

If you have any doubts related to this topic, you ask into the comment. If you have any problem in mathematics you can post your problem in the comment section. You will get the answer.

I hope you have learned it properly.