Irrational numbers are those numbers which are not rational: that is, they cannot be
written as a fraction. Famous examples of irrational numbers include π, e and √2. The decimal version of any irrational number neither terminates nor recurs. For example,
π can be written as 3.141592… but this series of digits will continue infinitely. The world
record for the number of digits calculated for π currently stands (as of 2015) at 2.7 trillion
digits. For this reason, any computer representation of an irrational number will actually
be a very close approximation.