**Real Number:**

All
numbers whether rational and irrational comes under the category of real number

Example:
1,500.22/3,1/3,√2 etc.

**Rational Numbers:**

A
number that can be represented in the form

**p/q**where**p**and**q**are integers and**q**is not zero.
Example:
2/3, 1/10, 8/3 etc. They can be finite decimal numbers, whole numbers,
integers, fractions.

**Irrational Number:**

An irrational
number is a number that cannot be written as a ratio (or fraction).
In decimal form, it never ends or repeat.

Example:
√2,π, Other famous
irrational numbers are the golden ratio, a number with great importance to
biology:

**Integers:**

Numbers
with no fractional part i.e.

**q=1 in p/q**form (always).It includes:
All
Counting Numbers(1,2,3,4,5,6,……),
ZERO(0) & Negative of all counting
Numbers(-1,-2,-3,-4,-5,-6,……..)

**Natural Number:**

The
natural (or counting) numbers are 1, 2, 3, 4, 5, etc. There are infinitely many
natural numbers.

The
set of natural numbers, {1, 2, 3, 4, 5,……}, is sometimes written N for short.

**Even numbers:**

The
numbers divisible by 2 are even numbers. e.g., 2, 4, 6,8,10 etc. Even numbers
can be expressed in the form 2n where n is an integer other than 0.

**Odd numbers:**

The
numbers not divisible by 2 are odd numbers. e.g. 1, 3, 5, 7, 9 etc. Odd numbers
are expressible in the form (2n + 1) where n is an integer other than 0.

**Composite numbers:**

A
composite number has other factors besides itself and unity .e.g. 8, 72, 39
etc. A real natural number that is not a prime number is a composite number.

**Prime numbers:**

The
numbers that has no other factors besides itself and unity is a prime number.

Example:
2, 23,5,7,11,13 etc. Here are some properties of prime numbers: