An introduction to the framework
A worksheet in Microsoft Excel is divided into over 1 million rows and over 16,000 columns. The rows are labeled 1, 2, 3, and so on to 1,048,576, and the columns are labeled A, B, C, and so on to XFD. The rows and columns intersect to form over 16 billion cells in one worksheet. However, since a cell is identified by the column and row that intersect to form it, each cell has a unique identification that is conventionally written as the intersecting column and row. Thus, at the intersection of column UV and row 59, we have the cell UV59. There is no other cell UV59 on that worksheet in that workbook on that computer. This feature forms the basis for the referencing framework in Excel. It means that you can use the contents of any cell simply by including its cell reference in a formula.
The following screenshot gives the simplest example of this. By typing =D4 in cell F5, the contents of cell D4, Happy day, have been duplicated in cell F5: