None of this has to do with the capacity of the mind to add and subtract, solve problems, etc. This capacity involves different areas of the brain.
In much of my writing, I talk about the mind and its impact. Sometimes I refer to ego-mind, but usually just mind. That is because in common parlance, the mind is synonymous with ego-mind; that is the "self" that everyone refers to.
So it is important to make clear that when in my writing I discuss all the problems that flow from the mind, it is the ego-mind I am talking about, certainly not Buddha mind. And the process of cleansing our mind, or purifying our heart, is the process of moving us along that continuum from ego mind to Buddha mind.
The mind, understood thus, is never your adversary, a source of problems; the ego-mind, yes, but not the mind as a whole. On the contrary, the mind is the source of growth, spiritually and otherwise.