Answer:
The correct answer to the question: What part of her brain is at work, when Penelope is adding fractions while taking a math test, is a complex one, and now science knows that there is not one, but three regions that act together in all mathematical activities: the posterior parietal cortex, ventrotemporal occipital cortex and the prefrontal cortex.
Step-by-step explanation:
According to the latest research studies in neuroscience, and published in such journals as the Journal of Neuroscience, it has been discovered that, unlike what it used to be believed, that there was one simple place where mathematical thinking was performed, now there are three regions of the brain that carry out this process. These three, and depending on their size and number of grey matter, will ensure more, or less, mathematical skills, in a person. These three regions are interconnected and act together whenever a person is facing mathematical problem-solving.