Profile of High School Students Problem Solving skills and the Implementation of PBL Model Assisted by Digital Books on Dynamic Fluid Material. J. Innov. Technol. Sustain. Educ. [Internet]. 2026 Apr. 14 [cited 2026 Apr. 17];2(1). Available from: https://journal.i-ros.org/index.php/JITSE/article/view/118