P. . Siregar, A. Armanto, and Z. . Matondang, “IMPROVEMENT OF CRITICAL THINKING ABILITY AND LEARNING INTEREST MATHEMATICS USING MODELS PROBL EM BASED LEARNING ON STUDENT CLASS V SD IT NURUL ILMI PADANG SIDEMPUAN”, SIJEL, vol. 3, no. 1, pp. 159–179, Mar. 2023.