In most mathematical equations, real numbers are used. As it is well known, the product of two real numbers can never be negative. So, the imaginary number i is brought in. The first step to find the square roots of negative numbers is to express imaginary numbers as the product of i and a real number. These are all complex numbers.
Multiplication is possible.
Complex numbers can be used to make beautiful pictures called fractals. They are drawn on the complex plane. Fractals can be found everywhere, either in nature or man-made.