The field of mathematics presents a significant challenge for students with ADHD and learning disabilities. By describing the characteristics of these disorders, it is possible to understand their impact on a specific skill - solving verbal math problems. Research on the application of specific cognitive strategies in mathematics, as well as the SRSD teaching model, has reported contributions for this population in various areas. Given the smaller number of studies conducted on this topic in the Croatian context and the lack of recognition of this type of support in practice, the aim of this research is to describe the application of a specific cognitive learning strategy in the field of mathematics "Step by Step" in combination with mnemonics in working with a student with ADHD and learning disabilities, and to gain insights into their contribution to improving self-regulation skills, learning motivation, and academic success. The study used the method of observation and semi-structured interviews with the student with ADHD and learning disabilities and her mother. Based on the observations, the process of teaching the strategy was described, while the recorded interviews were transcribed. The collected written forms of information were qualitatively analyzed and interpreted. The results of the research reported characteristic difficulties of student in the field of mathematics, among which the occurrence of secondary difficulties stood out. Furthermore, the themes indicated a positive experience of teaching the strategy and observed changes through the application of the strategy, such as generalization, independence, emotional benefits and overall progress. Additionally, the research showed the contribution of the strategy application to self-regulation skills, learning motivation, and academic success. Finally, the research highlighted the importance of family and school collaboration, the application of individualized approaches, and the need for introducing the teaching of specific cognitive strategies in the direct work of educational rehabilitators.