Thanks Frank ... I've emailed the Crystal Ball link to sis-in-law. She didn't elaborate whether she has an explanation for the Mind Reader puzzle, but if she does, she won't have much trouble with the Crystal Ball.
I've posted my own explanation of how the Mind Reader does his thing over on Kev's board which you linked. I'll just mention in passing that I'm certainly no math whiz ... I simply have a natural affinity with nine's, being pretty much a square myself. It's when I'm at sixes and sevens that I'm completely at a loss.
I appreciate the links.