We define the imaginary unit, i, as the square root of negative 1. Then we introduce the Complex Numbers. A complex number is a number of the form a + b*i . a is the real part and b*i is the imaginary part. Next I explain how calculate the integer powers of the imaginary unit, i. Then, I explain how to add, subtract, multiply and divide complex numbers. In the next video, Complex Numbers Part II ( here: http://bit.ly/2ipGyvo ) we go on with powers and roots of Complex Numbers in Polar Form.