We conducted an experiment to determine the impact of short-term pressure on 1,228 Grade 8 students' outcomes when performing simple math exercises. We required all students to complete 100 simple math questions for 90 seconds. We analysed students' results and then divided them into three groups: (i) a control group who did nothing; (ii) a group who performed an easy task; and (iii) a group who performed a difficult task. Finally, we required all students to solve another 100 simple math questions in 90 seconds and used a Bayesian model to compare the results of the three groups. We discovered that students who successfully solved complex tasks received higher outcomes within short periods than those who succeeded in the easy task. However, students who failed to solve either the easy or the problematic tasks received lower results than those who did nothing between the two attempts. Also, we found no differences between the results of male and female students. The findings shed further light on the Yerkes-Dodson law about the influence of stress and distress on students' performances.