"The educational reform, 12-year basic education, was implemented broadly and deeply from elementary to high school in 2019. The reformed curriculum proposed competency-based instruction, which corresponds with contemporary educational theories advocated by many countries. It is expected that the educational reform would bring about positive changes for schools. Over one-year implementation of the reformed curriculum, the public began to be concerned with the curriculum's effects. However, educational studies that investigate the conduct and the effects of the reformed curriculum is scant. Therefore, this study took the typical unit of seventh-grade mathematics, algebraic word problems with one unknown, as a case to examine the difference of the mathematics textbooks design between the reformed curriculum and the old one by conducting mix-methods. Research findings suggest that three textbook publishers did not significantly change mathematics task types and promote the tasks' cognitive demands. Furthermore, many mathematics tasks were identified as copying the last version of the textbooks. This study discusses the reason that underpins the phenomenon and proposed suggestions accordingly."