Abstract
This study aims to develop a fairytale book based on Science-Mathematics suitable to enhance critical thinking skills and curiosity and reveal the effectiveness of the fairytale book based on Science-Mathematics to improve critical thinking skills and curiosity. Moreover, this study was conducted at two State Elementary Schools in Yogyakarta, Indonesia. This study employed the R & D method adapted by Borg and Gall consisting of 10 steps, including (1) collecting information, (2) planning, (3) developing a preliminary xform of product, (4) conducting preliminary field testing, (5) revising main product, (6) conducting main field testing, (7) revising operational product, (8) conducting operational field testing, (9) revising final product, and (10) conducting dissemination and implementation. Moreover, the data were collected through interviews (need analysis), tests, observations, and questionnaires. Before data collection, the products’ validation was conducted by involving learning media experts, material experts, linguist experts, and teachers and students. After that, data were analysed using a MANOVA test with a significance level of 5%. The result showed that the Science-Mathematics-based fairytale book was feasible based on learning media, material, and linguist experts with a predicate of “very goodâ€. Additionally, the Science-Mathematics-based fairytale book effectively improved critical thinking skills and curiosity with medium effectiveness.