In this work, generalizing our previous results, we determine in an original and the simplest way three most important thermodynamical characteristics (Bekenstein-Hawking entropy, Bekenstein quantization of the entropy or (outer) horizon surface area and Hawking temperature) of Kerr-Newman black hole. We start physically by assumption that circumference of Kerr-Newman black hole (outer) horizon holds the natural (integer) number of corresponding reduced Comptons wave length and use mathematically, practically, only simple algebraic equations. (It is conceptually similar to Bohrs quantization postulate in Bohrs atomic model interpreted by de Broglie relation.)