In spreadsheets, columns are referred to with letters.
You can refer to columns as numbers by using a formula.
To display the column numbers, do the following steps:
Select a cell.
On the Formula Input Line, enter =column(cell_reference) and
press Enter. For example, to display the column number of cell D7,
enter =column(D7). If you leave the cell_reference empty,
the column number of the current-selected cell is displayed.