<![CDATA[ABSTRACT The limitations of student worksheets (LKPD) in IPAS learning within the Lepak Cluster are reflected in activities that remain centered on material summaries and closed-ended exercises, while problem-solving processes have not yet been systematically facilitated. This condition provided the basis for developing a Challenge-Based Learning (CBL)-based student worksheet designed to connect challenges, investigation, solution development, and reflection within a coherent learning experience. The study employed Research and Development using the ADDIE model through needs analysis, design, development and validation, field testing, and product evaluation. The implementation involved 80 sixth-grade students from four schools, comprising 40 students in the experimental group and 40 in the control group. Data were collected through expert validation, teacher and student responses, and problem-solving tests. The analysis included validity and practicality assessments, N-Gain, normality and homogeneity tests, and an independent samples t-test. The product obtained scores of 70 from the material expert, 70 from the design expert, and 71 from the language expert, all categorized as highly valid. Practicality reached 92.67% based on teacher responses and 85.96% based on student responses, both categorized as highly practical. The experimental group achieved an N-Gain of 0.60 (60%; moderate), compared with 0.26 (26%; low) in the control group, with a significant difference (t = 16.818; Sig. 2-tailed = 0.000). These findings position the CBL-based student worksheet as a learning resource capable of facilitating problem-solving through a more structured learning experience for elementary school students. ABSTRAK Keterbatasan LKPD dalam pembelajaran IPAS di Gugus 1 Lepak terlihat dari aktivitas yang masih berpusat pada ringkasan materi dan soal tertutup, sementara proses problem solving belum difasilitasi secara bertahap. Kondisi tersebut menjadi pijakan pengembangan LKPD berbasis Challenge-Based Learning (CBL) untuk menghadirkan pengalaman belajar yang menghubungkan tantangan, penyelidikan, penyusunan solusi, dan refleksi. Penelitian ini menggunakan Research and Development dengan model ADDIE melalui analisis kebutuhan, perancangan, pengembangan dan validasi, uji coba, serta evaluasi produk. Implementasi melibatkan 80 siswa kelas VI dari empat sekolah, dengan 40 siswa pada kelompok eksperimen dan 40 siswa pada kelompok kontrol. Data diperoleh melalui validasi ahli, respons guru dan siswa, serta tes problem solving. Analisis mencakup penilaian validitas dan kepraktisan, N-Gain, uji normalitas, homogenitas, dan independent samples t-test. Produk memperoleh skor 70 dari ahli materi, 70 dari ahli desain, dan 71 dari ahli bahasa dengan kategori sangat valid. Kepraktisan mencapai 92,67% dari guru dan 85,96% dari siswa dengan kategori sangat praktis. N-Gain kelompok eksperimen mencapai 0,60 (60%; sedang), sedangkan kontrol 0,26 (26%; rendah), dengan perbedaan signifikan (t = 16,818; Sig. 2-tailed = 0,000). Temuan tersebut menempatkan LKPD berbasis CBL sebagai perangkat yang dapat memfasilitasi problem solving melalui pengalaman belajar yang lebih terarah pada siswa sekolah dasar.]]>
