(1) study pre-service secondary mathematics teachers’ learning of DGS skills by focusing on selected LS groups (i.e. cases); (2) conduct an in-depth study of each selected LS group;
(3) study each selected LS group’s learning of DGS skills; and
(4) study the cases of participants’ skills of using DGS to teach secondary school mathematics. Thus, the case study was chosen as an appropriate research design for this study as it fits the main characteristics of case study research (Gall, Gall & Borg, 2003).