Excel File Not Sorting

I have an acces table that was imported to an excel worksheet. I wish to sort by one column. What has been happening is the number without dashes are on the top of the column and the numbers with dashes appear at the bottem of the column. The only way to get a proper sort is to add a single quote symbol(‘) in each cell before the number in the particular I am trying to sort by and then it will sort properly. The proper sort being regardless of dashes or no dashes the numbers are in a propersort. Is there an easier way to make this happen? I appreciate any help on this. Thank you

Markus