[Jensson]

Maybe a lot of people suffer from a degree of dyscalculia, but in my experience if you do it a lot you just stop making mistakes. Not just me, many others I've seen reliably do calculations pretty quick without making errors, you just do everything twice as you go and then arithmetic errors go to basically 0.

But I do acknowledge that there are probably some or many humans that maybe can't reach that level of reliability with arithmetics.