The article asks about the minimal number of persons required for achieving a probability 1/2 that (a.) At least two share a birthday, (b.) At least one shares the reader's birthday. A basic question about the necessary number of checks underlies both problems.

As the number of independent tosses of a fair coin grows, the rates of heads and tails tend to equality. This is misinterpreted by many students as being true also for the absolute numbers of the two outcomes, which, conversely, depart unboundedly from each other in the process. Eradicating that misconception, as by coin-tossing experiments,…

The article presents an attempt to analyse Monty's dilemma by means of conversational formula-free dialogues and to simulate the problem by composing isomorphic stories. The crucial roles of specifying the underlying scenarios and explicating epistemic and probabilistic assumptions are highlighted.

Two contestants debate the notorious probability problem of the sex of the second child. The conclusions boil down to explication of the underlying scenarios and assumptions. Basic principles of probability theory are highlighted.

When two sealed envelopes contain money, one twice as much as the other, a player should be indifferent between them. But when one envelope is opened, one's decision should vary as a function of the observed value and one's subjective probabilities.