How many decimal places of π do you know? π is one of those numbers we call irrational . Rational numbers can be described as the ratio of two whole (integer) numbers. But π can not. There are no integers ‘a’ and ‘b’ such that a/b = π. This is true for many (actually infinite) other numbers such as √2 or √3. But π is a little different. It is transcendental as well. Either way, irrational numbers, when written out as a decimal expansion, never ends and never repeats. We can never write out all the numbers to fully account for its’ value. At least these are the conclusions of a body of mathematics called ‘real