Answer: Your answer is the Left Parietal Lobe
Step-by-step explanation:
A study involving 18 healthy young males doing simple arithmetic problems showed the left inferior parietal lobe, left precentral gyrus, left superior parietal lobe, left supramarginal gyrus, and left middle temporal gyrus. This supported the hypothesis that the human brain relatively activates its left hemisphere more compared with the right hemisphere when solving arithmetic problems.
Therefore, your answer is the left parieta lobe.