In pi what number occurs the most and how many times?

Answer 1

pi is a transcendental number. That means that it has a non-terminating, non-recurring decimal representation. That, in turn, means that nobody can ever identify all the digits of pi (except if counting in base pi, and that does not really help). And since there are an infinite number of digits it is always possible that the next stretch of digits will change the digit that is the most common so far.