Hasna, H.R., Fajriyah, K. and Saputra, H.J. 2021. The Effect of Blended Learning Based on The Problem-Based Learning Model Assisted by Puzzle Media on The Critical Thinking Skills of Fifth Grade Students on Ecosystem Themes. Journal of Education Technology. 5, 1 (Apr. 2021), 14–22. DOI:https://doi.org/10.23887/jet.v5i1.29770.