Each cell can be referenced by a combination of its column letter (A through Z, then AA to ZZ, AAA to ZZZ, etc.) and row number (1 and beyond) for a total of 2,147,483,648 rows and columns. For example, D50 refers to the cell at the intersection of column D and row 50. To refer to a range of cells, enter the reference for the cell in the upper-left corner of the range, a colon (:), and then the reference to the cell in the lower-right corner of the range.