Here is a YouTube video about Complex Numbers Part Imaginary but Really Simple, and is part of a growing collection of videos I have found to be useful. The reason is understanding what complex numbers are and being able to do mathematics with real and imaginary components and understanding science related to software defined radio.
This tutorial, "Complex Numbers Part Imaginary but Really Simple" is free education you can watch, which will help you deepen your knowledge and be better prepared for licence exams, schoolwork, or operating radio equipment.