We are all familiar with the fact that every real number can be expressed as a decimal (or has a decimal expansion). Such expansions are of course useful in allowing an easy comparison of the size of numbers, convenient addition, and so forth.
Issue 2
To grasp the nature of the contents of this article, consider the four figures in the diagram.
Issue 3
A theorem of twentieth century mathematics which must surely earn a place in any list of the great theorems of mathematics, is the theorem of Kurt Gödel concerning the existence of undecidable statements in formalised arithmetic.