“…Due to the importance of DEs, the topic has attracted many researchers, and the literature shows that a number of researches (e.g. Artigue, 1989;Blanchard, 1994;Boyce, 1994;Chau & Pluvinage, 1999;Kallaher, 1999;Habre, 2000;Rasmussen, 2001;Kwon et al, 2003;Saglam, 2004;Arslan, 2005;Raychaudhuri, 2008) and projects (Consortium for Ordinary Differential Equations Experiments in Harvey Mudd College; The Boston University Ordinary Differential Equations Project) have been carried out on the teaching of DEs. Nevertheless, most of these studies are about new approaches to teaching DEs and several researchers have pointed out a shortage of studies on students' understanding of DEs (Kwon, 2002;Habre, 2003;Rowland & Jovanoski, 2004;Raychaudhuri, 2008).…”