Reskina, Saragih, S., Suanto, E. and Maimunah 2023. Student Errors Analysis Problem-Solving based Castolan Theory on Relations and Functions Material. Numerical: Jurnal Matematika dan Pendidikan Matematika. 7, 1 (Jun. 2023), 157–166. DOI:https://doi.org/10.25217/numerical.v7i1.2895.