Previous research on social facilitation and inhibition showed that people are more successful on simple and well-trained tasks when they are performed in front of the audience and that performance is impaired when complex and new tasks are solved in front of the audience. The aim of this study was to examine whether social facilitation / inhibition occurs on simple and complex mathematical tasks and to examine the effect of personality traits on the occurrence of these phenomena. Seventy students of psychology participated (5 men and 65 women) in the study. The research included the Big Five Inventory, Rosenberg's Self-Esteem Scale, and two forms of simple and complex mathematical tasks. In the first phase, after completing two personality questionnaires, the participants solved simple and complex mathematical tasks by themselves or in front of the audience that was made by the experimenter and another student. For each task group, participants had 3 minutes to solve the tasks. In the second phase of the study, each participant received a different task form, reversed task complexity and different condition of task-solving (alone or in front of the audience) in relation to the first phase. The results showed that participants were equally successful in solving mathematical tasks when they were alone and when they were in front of an audience. However, there is a significant interaction between neuroticism and condition of task-solving, and between neuroticism, condition of task-solving and task complexity. Low-neurotic subjects showed improved performance on math tasks in front of audience, while high-neurotic subjects were more successful on math tasks when solving the tasks alone. Low-neurotic subjects showed improved performance on simple math tasks when they were solving them in front of an audience, while high-neurotic subjects showed improved performance on simple tasks when solving them on their own. High-neurotic subjects were particularly successful on complex tasks when solving them alone, while low-neurotic subjects had equally successful performance on complex tasks in both conditions. Given these results, we can conclude that high levels of neuroticism can lead to reduced effectiveness when a person is performing different tasks. For optimal performance of emotionally unstable people, working conditions and conditions under which such people demonstrate their knowledge and skills need to be adapted to suit their needs, as they are more successful in situations in which they work alone.