<![CDATA[Elementary students’ mathematical numeracy skills need to be strengthened through concrete, interactive learning that corresponds to their developmental characteristics. This study aimed to develop Magic Number learning media assisted by the Teams Games Tournament (TGT) model to improve the mathematical numeracy skills of second-grade elementary school students. This study employed a Research and Development (R&D) approach using Sugiyono’s development procedures combined with the ADDIE model. The product focused on addition and subtraction of whole numbers up to 20. The trial involved 24 second-grade students of SD Negeri Tegalrejo 01. Data were collected through expert validation, numeracy tests administered before and after learning, and teacher and student response questionnaires. The developed media met the feasibility criteria after validation and revision. Its implementation improved students’ ability to understand mathematical concepts and procedures, apply concepts to routine problems, and use reasoning to solve non-routine problems. Statistical analysis indicated a difference in numeracy performance before and after using the media. Magic Number assisted by TGT is considered feasible, effective, and practical for supporting the improvement of mathematical numeracy skills among second-grade elementary school students. ABSTRAK Kemampuan numerasi matematika murid sekolah dasar perlu diperkuat melalui pembelajaran yang konkret, interaktif, dan sesuai dengan karakteristik perkembangan murid. Penelitian ini bertujuan mengembangkan media Magic Number berbantuan model Teams Games Tournament (TGT) untuk meningkatkan kemampuan numerasi matematika murid kelas II. Penelitian menggunakan metode Research and Development (R&D) dengan prosedur pengembangan Sugiyono yang dipadukan dengan model ADDIE. Produk dikembangkan pada materi operasi hitung penjumlahan dan pengurangan bilangan cacah sampai 20. Uji coba melibatkan 24 murid kelas II SD Negeri Tegalrejo 01. Data diperoleh melalui validasi ahli, tes numerasi sebelum dan sesudah pembelajaran, serta angket respons guru dan murid. Media yang dikembangkan memenuhi kriteria kelayakan setelah melalui validasi dan revisi. Penggunaan media menunjukkan peningkatan kemampuan murid dalam memahami konsep dan prosedur matematika, menerapkan konsep pada masalah rutin, serta menggunakan penalaran untuk menyelesaikan masalah nonrutin. Hasil analisis statistik menunjukkan adanya perbedaan kemampuan numerasi sebelum dan sesudah penggunaan media. Magic Number berbantuan TGT dinilai layak, efektif, dan praktis untuk mendukung peningkatan kemampuan numerasi matematika murid kelas II sekolah dasar.]]>
