Tujuan penelitian ini adalah untuk mengembangkan video pembelajaranmatematika berbasis STEM (Science, Technology, Engineering, and Mathematics) pada kelas IX A SMP Negeri 1 Campalagian yang valid, praktis dan efektif. Jenispenelitian ini adalah penelitian dan pengembangan atau Research &Development (R&D). Tahapan pengembangan model ADDIE terdiri dari Analysis, Design, Development, Implementation, dan Evaluation. Subjek penelitian ini adalah siswakelas IX A SMP Negeri 1 Campalagian. Instrumen yang digunakan dalampenelitian ini adalah (1) lembar validasi ahli untuk mengukur validitas media, (2) lembar validasi ahli untuk mengukur validitas materi, (3) lembar angket Responssiswa dan (4) lembar angket Respons guru untuk mengukur kepraktisan media, dan (5) lembar angket tes hasil belajar siswa untuk mengukur keefektifan media. Hasil penelitian ini menunjukkan bahwa video pembelajaran matematika berbasisSTEM dinyatakan valid oleh validator diperoleh ahli media dengan rata-rata total sebesar 3 dan validator ahli materi dengan rata-rata total sebesar 3. Videopembelajaran matematika berbasis STEM dinyatakan praktis dilihat dari Responsguru dengan rata-rata total 3,5 dengan kategori sangat praktis dan Respons siswadengan rata-rata total 3,8 dengan kategori sangat praktis. Video pembelajaranmatematika berbasis STEM dinyatakan efektif karena rata-rata siswa mampumelebihi nilai kriteria ketuntasan minimal dilihat dari ketuntasan klasikal sebesar 91,30% dan berada pada kategori sangat baik. Berdasarkan data-data tersebut, dapat disimpulkan bahwa video pembelajaran berbasis STEMyangdikembangkan oleh peneliti memenuhi kriteria valid, praktis dan efektif sertalayak digunakan sebagai video pembelajaran matematika.

The purpose of this study was to develop a valid, practical and effectiveSTEM (Science, Technology, Engineering, and Mathematics) based mathematicslearning video for class IX A of SMP Negeri 1 Campalagian. The type of thisresearch is research and development (R&D). The stages of developingtheADDIE model consist of Analysis, Design, Development, Implementation, danEvaluation. The subjects of this study were class IX A of SMP Negeri 1Campalagian. The instruments used in this study were (1)expert validation sheetsto measure the validity of the media, (2) expert validation sheets to measure thevalidity of the material, (3) veron dowa questionnaire sheets and (4) teacher response questionnaire sheets to measure the practicality of the media, and(5)
student learning outcome test questionnaire sheets to measure the effectiveness of the media. The results of the study indicate that the STEM-based mathematicslearning video was declared valid by the validator obtained by the media expert with a total avarage of 3 and the material expert validator with a total average3. The STEM-based mathematics learning video was declared practical as beenfromthe teacher’s response with a total average of 3,5 with a very practical categoryand the student’s response with a total average of 3,8 with a very practical category. The STEM-based mathematics learning video was declared effectivebecause the average student was able to exceed the minimum completness criteriavalue as seen from the classical completennes of 91,30% and was in the verygoodcategory. Based on these data, it can be concluded that the STEM-based learningvideo developed by the researcher meets the cricteria for valid, practical andeffective and is suitable for use as a mathematics learning video.