Development of Local Instruction Theory Teaching Materials to Improve Mathematical Problem-Solving Ability - Dwi Antari Wijayanti; Mimi Nur Hajizah; Pinta Deniyanti Sampoerno (Department of Mathematics Education Program IPI Garut, 2025)
Penelitian ini dilakukan untuk mengatasi kurangnya bahan ajar kontekstual yang dapat mendukung kemampuan pemecahan masalah siswa melalui pengalaman belajar yang bermakna. Tujuan dari penelitian ini adalah mengembangkan bahan ajar berbasis Local Instruction Theory (LIT) yang valid, praktis, dan efektif dalam meningkatkan kemampuan pemecahan masalah matematis. Penelitian ini menggunakan metode penelitian dan pengembangan (R&D) dengan model ADDIE, dan dilaksanakan pada bulan Maret hingga Juni 2024 di SMP Negeri 216 Jakarta. Subjek penelitian adalah 66 siswa kelas VIII yang dibagi ke dalam kelompok eksperimen dan kelompok kontrol. Teknik pengumpulan data meliputi angket validasi ahli, angket respon siswa, dan tes pemecahan masalah matematis. Data dianalisis secara kuantitatif melalui skala Likert, uji normalitas dan homogenitas, serta uji t sampel independen. Hasil penelitian menunjukkan bahwa bahan ajar yang dikembangkan memiliki tingkat validitas sangat tinggi (87,72%), kepraktisan tinggi (88,9%), dan efektif dalam meningkatkan kemampuan pemecahan masalah, ditunjukkan dengan perbedaan skor posttest yang signifikan antara kelompok eksperimen dan kontrol. Penelitian ini menyimpulkan bahwa bahan ajar berbasis LIT mampu meningkatkan kemampuan pemecahan masalah matematis siswa dan direkomendasikan untuk diimplementasikan dalam pembelajaran matematika secara lebih luas. This research was conducted to address the lack of contextual teaching materials that can support students' problem-solving abilities through meaningful learning experiences. The purpose of this research is to develop teaching materials based on Local Instruction Theory (LIT) that are valid, practical, and effective in improving mathematical problem-solving abilities. This research used a research and development (R&D) method with the ADDIE model, and was conducted from March to June 2024 at SMP Negeri 216 Jakarta. The research subjects were 66 eighth-grade students who were divided into experimental and control groups. Data collection techniques included expert validation questionnaires, student response questionnaires, and mathematical problem-solving tests. Data were analyzed quantitatively using a Likert scale, normality and homogeneity tests, and independent sample t-tests. The results showed that the developed teaching materials had a very high level of validity (87.72%), high practicality (88.9%), and were effective in improving problem-solving skills, as indicated by a significant difference in posttest scores between the experimental and control groups. This study concluded that LIT-based teaching materials were able to improve students' mathematical problem-solving skills and were recommended for broader implementation in mathematics learning.