Fix text-formatted numbers

I imported a lot of data from a PDF extracted to Excel then to Smartsheet. I tried to create a conditional format based on a column of numbers e.g. 1, 2, 3, 3.1, 3.2, 4 etc however it did not work. If I re-type the number in manually, it works for that row. My guess is the number is formatted as text. Is there a way to fixe this considering there are 1000's of rows?