I play around with adding, subtracting, or multiplying license plate numbers. Does that count?

I am so rusty, that I just do add and subtract.

On the other hand, my grandparents, and father, could look at financial documents and do the calculations in their head.

People I know who stayed in finance longer than me, can crunch numbers rapidly.

I am around numerate people most of the time, so the occasions where I find I am the faster calculator around are jarring.

There are many conversations that go adrift because we can’t crunch numbers fast enough.

Is it a net loss to humanity in the face of the gains we obtained. Nope.

Is mental fitness of value to me, the same way physical fitness is of value to me? Yes, very much.