Objectives The purpose of this study was to examine the difference between mathematical problem-solving ability and smartphone addiction according to the experience of coding play in 5-year-old children, and the relationship between mathematical problem-solving ability and smartphone addiction.
 Methods To achieve the objectives of this study, 135 5-year-old children enrolled in early childhood education institution located in Gyeonggi Province were selected as research subjects. Data were collected through interviews with the children and questionnaires administered to their parents. Descriptive statistics, t-tests, and correlation analyses were conducted using the SPSS WIN 24.0 program to analyze the collected data.
 Results First, it was found that children with coding play experiences demonstrated higher mathematical problem- solving abilities than those without such experiences. Additionally, children with coding play experiences showed higher abilities in number and operation, algebra, and measurement. Smartphone addiction was also higher in children with coding play experiences, and they exhibited higher severity and resistance to smartphone addiction. Second, as the mathematical problem-solving abilities of children with coding play experiences increased, smartphone addiction decreased, and impulsive-compulsive use of smartphones was lower. Moreover, among the subfactors of mathematical problem-solving abilities, higher geometric and statistical abilities were associated with lower severity of smartphone addiction, withdrawal symptoms, daily life issues, and interpersonal conflicts. In contrast, there was no significant correlation between mathematical problem-solving abilities and smartphone addiction in children without coding play experiences.
 Conclusions The study suggests that early experiences with coding play can contribute to the development of mathematical problem-solving skills in 5-year-old children. However, it also indicates a potential risk of smartphone addiction. Nevertheless, the study demonstrates that higher mathematical problem-solving abilities in children with coding play experiences are associated with a lower risk of smartphone addiction. This highlights the importance of mathematical problem-solving skills, which can reduce the risk of early childhood smartphone addiction while enhancing the educational effects of coding play.