Difficulties in calculation can be detected in initial mathematics classes. Difficulties can be the result of many factors, and often there is an interaction of different difficulties or a relation to other specific difficulties, such as dyslexia. In the first grade of elementary school, students may have difficulties acquiring the concept of numbers, adding and subtracting up to 10, understanding place values, and adding and subtracting numbers up to 20, especially with the transition to ten. In eliminating and reducing these difficulties, teachers, professional associates, and parents can help through cooperation and mutual effort. As part of this work, qualitative research (a case study) was conducted. It examines the experiences and attitudes of one teacher and her work with students who have difficulties with calculation, as well as the relationship with the parents of such students. The goal of the research was to explore the challenges that teachers face when working with students who have difficulties with calculation and also to explore ways to solve these challenges. The results showed that the lack of professional help in working with these students was the biggest challenge for the teacher. Because of this, the teacher had to come up with different solutions that she found useful and efficient. Some of these solutions are didactic materials, the use of different models of arithmetic to help explain mathematical content, and others that will be mentioned in this paper.