View more at http://www.MathTutorDVD.com. In this lesson, we will move beyond imaginary numbers and discuss the concept of a complex number. Complex numbers consist of a real part added to an imaginary part. The real part can be plotted on a number line, and the imaginary part can be plotted on another number line only for imaginary numbers. Together, the complex numbers can be plotted in the complex plane which we will discuss in this lesson.