\input zb-basic \input zb-matheduc \iteman{ZMATH 2011c.00718} \itemau{Maher, Carolyn A.; Sran, Manjit K.; Yankelewitz, Dina} \itemti{Building an inductive argument.} \itemso{Maher, Carolyn A. (ed.) et al., Combinatorics and reasoning. Representing, justifying and building isomorphisms. New York, NY: Springer (ISBN 978-0-387-98131-4/hbk; 978-94-007-0614-9/hbk; 978-0-387-98132-1/ebook). Mathematics Education Library 47, 45-57 (2010).} \itemab Summary: In the previous chapters, we followed the strategies, schemes, and arguments built by second-, third-, and fourth-grade students as they worked on combinatorial tasks. In this chapter, we trace how Stephanie and her classmates tried to make sense of the inductive method of generating towers. This strategy was originated by Milin, but it was eventually adopted by many other students. We attempt to identify the moments at which individual students gained ownership of the inductive argument and explained their new understanding to others. \itemrv{B. Ruffer-Henn (B\"ohl-Iggelheim)} \itemcc{K23 C33 D53} \itemut{combinatorics; reasoning; combinatorial thinking; argumentation; educational research} \itemli{doi:10.1007/978-94-007-0615-6\_5} \end