Permasalahan yang melatarbelakangi penelitian ini ialah rendahnya pemahaman konsep siswa mengenai perkalian dan pembagian di kelas III. Hal ini disebabkan oleh beberapa faktor seperti siswa mengalami kesulitan dalam memahami perkalian dan belum menggunakan media untuk menunjang proses pembelajaran perkalian dan pembagian, Penelitian ini bertujuan untuk mengetahui kelayakan dan efektivan buku cerita matematika bergambar untuk meningkatkan pemahaman siswa pada elemen bilangan siswa Fase B di sekolah dasar. Metode penelitian yang digunakan ialah Research and Development (R&D) dengan model pengembangan ADDIE yang terdiri dari 5 tahapan yaitu: Analyze, Design, Development, Implementation, Evaluation. Subjek dalam penelitian ini adalah siswa kelas III sebanyak 33 orang siswa. Teknik pengumpulan data yang digunakan adalah observasi, wawancara, tes, angket dan penilaian penilaian produk oleh ahli. Data yang diperoleh dianalisis dengan menggunakan uji validasi isi, uji paired sampel t-test, dan perhitungan angket. Hasil analisis data kelayakan bahwa buku cerita matematika bergambar mendapatkan tingkat kevalidan yang tinggi dengan kategori sangat layak. Sedangkan analisis data keefektivan didapatkan dari hasil analisis uji-T paired sample test yang menunjukan bahwa diperoleh nilai thitung adalah 13,89 dan nilai ttabel adalah 1,693, dikarenakan nilai thitung > nilai ttabel maka dapat disimpulkan bahwa terdapat perbedaan yang signifikan antara nilai pre-test dan pos-test sehingga buku cerita matematika bergambar dikatakan efektif untuk digunakan.
Kata Kunci: Pemahaman Konsep, Buku Cerita Matematika Bergambar, Perkalian, Pembagian

He problem underlying this research was the low understanding of concepts among students regarding multiplication and division in the third grade. This was caused by several factors, such as students experiencing difficulties in understanding multiplication and not utilizing media to support the learning process of multiplication and division. This study aimed to determine the feasibility and effectiveness of illustrated mathematical storybooks to enhance students' understanding of number elements in Phase B at elementary school. The research method used was Research and Development (R&D) with the ADDIE development model, which consists of five stages: Analyze, Design, Development, Implementation, and Evaluation. The subjects of this study were 33 third-grade students. The data collection techniques employed were observation, interviews, tests, questionnaires, and product assessments by experts. The data obtained were analyzed using content validity tests, paired sample t-tests, and questionnaire calculations. The results of the feasibility analysis indicated that the illustrated mathematical storybook received a high validity level, categorized as very feasible. Meanwhile, the effectiveness analysis was derived from the paired sample t-test results, which showed that the obtained t-value was 13.89 and the t-table value was 1.693. Since the t-value was greater than the t-table value, it could be concluded that there was a significant difference between the pre-test and post-test scores, thus indicating that the illustrated mathematical storybook was effective for use.
Keywords: Concept Understanding, Illustrated Mathematical Storybook, Multiplication, Division.