This study was designed as an action research with the aim of overcoming the deficiencies of a first-grade student with a lower level of readiness in mathematics. The participant of the study was a first grader studying in a public primary school in the district of Haymana, Ankara during the second semester of the 2018-2019 academic year. The teacher's inclass observations, examination of the students' homework notebooks, and familial interviews were taken into consideration in the selection of the participant. Observations and interviews were conducted as a preliminary study to determine the student's level of readiness for mathematics lessons. İt was seen that there were familial and educational reasons for the students to have difficulty in learning mathematics subjects. İn addition, an action plan was prepared because the student was behind his peers in terms of adaptation to school, literacy, and social development and it was aimed to obtain the first term gains. The study revealed that the student was successful in activities such as rhythmic counting, meaningful counting, one-to-one correspondence, quantity comparisons, addition, and subtraction while his confusion with number conservation remained. As a result of the obtained findings, it is predicted that raising the awareness of parents about the readiness of children of preschool age will positively affect their school success and hinder the problems described here.