Then there is the old one about the Ouija Board. Story has it that a ouija board was asked what was going to happen in 1975, and in response the bloody thing exploded.
@Blondie
Of course, the “Ah buts” will protest that the demons are “in Tartarus”, a place of spiritual un-enlighenment, and so are incapable of putting two and two together. However, as one of the much maligned “Clergy of Christendom” once pointed out, the angels were there at the time of Eve’s creation - and if it were a simple matter of adding 6000 years to a certain date, then they should have been able to figure it out!