<p>In this study, we investigated the impact of congruent and incongruent gestures on the mental calculation of arithmetic operations. Three groups of students (aged 10–12) solved a set of verbal addition and subtraction problems under three different conditions: congruent-gesture, incongruent-gesture, and no-gesture. Each group of participants completed the problems in only one of these conditions. We conducted a mixed ANOVA to compare the number of correct answers and the mean response times for correct answers across the three conditions. The results showed that participants in the congruent-gesture condition achieved the highest accuracy and the fastest response times, whereas those in the incongruent-gesture condition showed the lowest accuracy and the slowest response times. Although the gestures in our study appeared to serve primarily a communicative function, we propose that their role in supporting communication can also facilitate the cognitive processes involved in mental arithmetic. We propose two possible explanations for the results. The first explanation concerns the role of congruent gestures in enhancing the mental simulation of arithmetic operations. The second explanation relates to the role of congruent gestures in strengthening embodied memories associated with arithmetic operations. Finally, we conclude that congruent gestures support not only memory processes but also the higher-order cognitive mechanisms involved in mental calculation. </p>