A real number is any number that can be placed on a number line that extends to infinity in both the positive and negative directions.
e.g 12, 45, 45.98, -0.985, -537
Let's consider an imaginary number i which is equal to square root of -1.
The square value of i, i2 = -1.
A complex number is any number that includes i such as
3i, 4 + 5i, -8i.
The real number is a subset of complex number which can be written as r + 0i.