If your column contains numeric values, you may need to change the formatting associated with those values. Click inside the column you want to format, so it appears selected. Click the Formatting tab, then choose the appropriate format for the values in your column.
In some instances, you might notice that your numeric values have already been formatted. For example, money symbols are already included in sales figures. Such formatting is inherited from metadata associated with the data source. However, you can override inherited formats whenever you want.