Numerical and symbolic representations are used extensively in physics problems. However, relatively little is understood about how students respond to these two representational formats when they are solving problems. This study examined the effect of the representational format (numeric vs symbolic) on the problem-solving performance, self-efficacy, and perceptions of students. Both quantitative and qualitative data were collected during this two-stage study: the first stage involved 100 10th graders solving problems that were in either the numerical or symbolic format, while in the second stage a subset of the students (6 from each group) solved physics problems in another format and were subsequently interviewed. The results showed that the numerical group significantly outperformed the symbolic group. Moreover, boys reported significantly higher self-efficacy than girls, even though no gender difference was found in their performance. In the problem-solving process, there were significant differences in how the interviewees performed when executing the plan and evaluating the solution between the two formats. We also found that most students perceived the symbolic problems as being more difficult than the numeric ones. These findings provide insights into better ways for teachers to support how students learn about physics problems in the numerical and symbolic representations.