You will need to split the one column into two columns and then you can delete the first one containing the letters.
Make sure the column to the right of your data is blank. If it is not, insert a new column by right-clicking on the column heading to the right and selecting Insert.
- Select the column with data by clicking its lettered column heading.
- From the Data menu, click Text to Columns...
- Within the conversion wizard, select Delimited. Click Next.
- Since there is a space between the letter and the numbers in your data, select Space as one of the delimiters. Click Next.
- Click Finish.
- Now you can delete the column with letters by right-clicking its column heading and selecting Delete.