This document discusses the areas of squares with different side lengths. It shows that squares with side lengths of 1, 2, 3, and 4 have areas of 1, 4, 9, and 16 square units respectively. There is a table that lists the side lengths and areas of these squares. The document then notes that when the areas are listed in order, there are 4 square units left over at the end that do not correspond to a square with a whole number side length.