\input zb-basic \input zb-matheduc \iteman{ZMATH 2015a.00887} \itemau{Syslo, Maciej M.; Kwiatkowska, Anna Beata} \itemti{Introducing students to recursion: a multi-facet and multi-tool approach.} \itemso{G\"ulbahar, Yasemin (ed.) et al., Informatics in schools. Teaching and learning perspectives. 7th international conference on informatics in schools: situation, evolution, and perspectives, ISSEP 2014, Istanbul, Turkey, September 22--25, 2014. Proceedings. Berlin: Springer (ISBN 978-3-319-09957-6/pbk). Lecture Notes in Computer Science 8730, 124-137 (2014).} \itemab Summary: In this paper we discuss a number of results and advices coming from our observations and didactical experience gathered when teaching about recursion in different contexts and on various education level (K--12 and tertiary). Knowing the difficulty in introducing, explaining and using recursion, we differentiate our approach, tools, and methods. Recursion can be introduced as a `real-life topic' -- see Section 2, and then software for visualization of recursive computations (Section 3) can be very helpful to overcome some difficulties by novices. Section 4 is on developing recursive thinking -- we use two popular topics -- generating Fibonacci number and printing digits of a number -- to explain how to introduce students to different aspects of recursion. Section 5 is addressed to complexity of recursive computations -- we discuss how to use recursion in a most effective way. We do not teach recursion as a separate topic or subject, it is rather a method and a tool, the way of thinking, used in various situations. It is redundant in some cases (Section 5.1), can be used as an approach alternative to iteration (Sections 2 and 4.2), but our main focus is on its properties as a concept which has a computational power in designing solutions of problems and running such solutions on a computer. \itemrv{~} \itemcc{P20 P50} \itemut{recursion; iteration; induction; algorithm visualization; Fibonacci numbers; Horner's rule; printing digits of a number; fast exponentiation; divide and conquer} \itemli{doi:10.1007/978-3-319-09958-3\_12} \end