In Excel 2010 just like any other version of Excel you usually see letters, ABC, in the columns. If you want to change Excel 2010 columns to numbers, like 123, or change them back to letters here is how to do it.
Change Excel 2010 Columns to Numbers
Open Excel 2010 and click on the File button. You will need to click on the Options as well.
From the Excel Options click the Formulas menu to the left. Over to the right under Working with formulas check the box for R1C1. This will change the columns letters to numbers.
After you finished click OK to close the menu. Here is how Excel will look like.
In this mode you will need to start typing your formulas as R1C1.
Change Excel 2010 Columns Back to Letters
To revert back to letters in the columns all you have to do is go back to File Options under formulas and uncheck R1C1 reference style.