This study examines entropy using Principal Component Analysis (PCA) and Singular Value Decomposition (SVDEn) in EEG signals to evaluate differences in neuronal activity between the left and right cerebral hemispheres both before and during an arithmetic task. The results indicate that the left hemisphere exhibits a significant rise in SVD entropy while performing the task, suggesting greater neuronal reorganization and complexity. In comparison, the right hemisphere shows no considerable changes, indicating that its involvement differs from person to person. By examining SVD entropy based on hemisphere, we can better define the changes in neuronal activity during mathematical operations, emphasizing the crucial function of the left hemisphere in performing the task.