The research was conducted to teach subtraction skills through the think-aloud method. The research was carried out through action research, one of the qualitative research methods. The study group in the research consists of a mildly intellectually disabled student. Data collection tools used in the research are criterion-referenced measurement tools employed in pre-test and post-test following action research process, performance record charts, teacher and student journals, and the think-aloud method student interview form. The research was recorded through tape recording during the whole process until the preparation and evaluation phases of the research action plans. According to the research results, it was observed that the student was able to perform the steps of subtraction independently; she obtained the information regarding the meaning of subtraction and told this. It is thought that this research will contribute to the literature since it improved the student’s academic and self-expression skills.

Keywords: Intellectual disability, Subtraction, Think-aloud method, Mathematics