Number formatting of the cell won't work as the values, you write, are text.
The Data/ Text-to-columns wizard should convert these to numbers as Hans wrote.
If it doesn't, there are probably some hidden, non-numeric characters in the value. The most common, especially if the data comes from the Web or an HTML document, is the no-break backspace (nbsp)
You can remove this with
=substitute(h2,char(160),"")
And then work on those values.