Real Numbers

        A Real Number is any positive or negative number which includes integers, rational and irrational numbers. In simple terms, all the numbers except complex number(numbers which have negative roots/numbers in the form "a + ib") can be called as Real Numbers.

Integers
        The set of all negative and positive numbers including zero but not decimal numbers(like 7.2, 85.5, 3/2.....) are called Integers.
        Set of Natural Numbers={-∞,.....-3, -2, -1, 0, 1, 2, 3, ….., ∞}

Natural Numbers
        The non-negative integers except 0 is called Natural Numbers. It is also called 'Counting Numbers'. 
        Set of Natural Numbers={1, 2, 3, 4, 5, 6, …..∞}

Rational Numbers
        A number in the form of p/q where p and q are integers and q≠0 that can also be expressed in terms of terminating or repeating decimals.
        Examples: 4, -8, 4.27, 33.3333333,...etc.

Irrational Numbers
        A number which can be expressed in the form of p/q where p and q are integers and q≠0 that are non-terminating and non-repeating decimals.
        Examples: π, e, √3, ∛13...etc.