Elizar Elizar, Anwar Anwar, Imam Rofiki, Puguh Darmawan, Yumiati, Endang Wahyuningrum
Cryptarithm problem-solving promotes algebraic thinking and supports students’ cognitive development, particularly in enhancing logical reasoning skills. This study examined the validity and reliability of a cryptarithm test using the Rasch measurement model to assess students’ cryptarithm problem-solving abilities and to investigate potential Differential Item Functioning (DIF) across gender and area. The study involved 281 senior high school students from four schools in Aceh, Indonesia, consisting of two rural and two urban schools. Students completed a six-item cryptarithm test, and the data were analyzed using the Rasch analysis method through WINSTEPS and SPSS 25. The findings indicated that the test items were valid and reliable, with no evidence of DIF. In terms of students’ problem-solving abilities, most participants demonstrated a moderate level of proficiency, with female students outperforming their male counterparts. Moreover, students from urban schools generally showed better performance than those from rural schools. These findings invite further discussion on the underlying factors contributing to gender and regional differences in performance on cryptarithm problems. © 2026 Elsevier Ltd.
Department of Mathematics Education, Universitas Syiah Kuala, Indonesia; Department of Mathematics Education, Universitas Negeri Malang, Indonesia; Master's Program in Mathematics Education, Universitas Terbuka, Indonesia
