“…Since the beginning of the twenty-first century, however, in light of educational effectiveness and improvement and together with the major role of textbooks in education (Fey & Matthes, 2018), research on textbooks' effectiveness, i.e., their contribution to educational outcomes, has gained in significance (Fan et al, 2013;Fuchs & Henne, 2018). Consequently, diverse topics were investigated, including design elements of textbooks such as illustrations, graphics, and tables, digital versus printed media, combining textbook with use of own materials (Fuchs & Henne, 2018; e.g., Wijaya, van den Heuvel-Panhuizen, & Doorman, 2015;Hadar, 2017), leading to a growing body of knowledge on criteria for evaluating textbooks' effectiveness in relation to student achievement. The most widely and vivid field of research on textbook effectiveness is situated within the field of mathematics (Schubring & Fan, 2013;Valverde et al, 2002), with most studies conducted at the primary education level (Fan et al, 2013).…”