Students' critical thinking skills are not optimal if they are only facilitated by learning resources in the form of printed books that have been available so far. Electronic books or e-books are learning resources for mathematics that serve various learning styles and can guide students to have critical thinking skills. This study aims to develop e-books used in the SSCS (Search, Solve, Create, and Share) learning model to strengthen critical thinking skills of elementary school students, evaluate their feasibility and effectiveness. This research method uses R&D (Research & Development). The implementation of the research at SD Gugus Ahmad Yani Korwilcam Dikpora Rakit Banjarnegara. Data were collected using interview techniques, questionnaires, and tests. Data obtained from the study were analyzed quantitatively and qualitatively. Based on the assessment of material experts, media experts, and educators as field validators, the e-book developed in the SSCS (Search. Solve. Create, and Share) learning model to strengthen critical thinking skills of elementary school students has criteria that are suitable for use based on the average score obtained by the validators of 87.7 which is in the valid criteria. The use of e-books in the SSCS (Search, Solve, Create, and Share) learning model has proven effective in strengthening critical thinking skills of grade VI elementary school students based on the results of the Mann Whitney test which showed an asymp sig. (2-tailed) value of 0.000 < sig. 0.05, which means that there is a significant difference in the learning outcomes of the pretest and posttest in the experimental class.