A numeric label in Microsoft Excel simply changes the way a column is labeled from the traditional letter to a number. It is better known as R1C1 Reference Style.
Using a numeric label for columns in Excel comes in handy when using macros. It can make it easier to computing row and column positions.
On a Mac, to set up Excel to use the R1C1 Reference Style, access the preferences under the Excel menu. Under the "General" settings, click the button for "Use R1C1 Reference Style.
On a PC, click on the Windows button and "Excel options." From here, open the formulas settings option and click "R1C1 Reference Style."