Feet & Inches

I do all my technical drawings in feet and Inches, does any one know if Rhino can work in both units at once and the info be in put in imperial.
i.e. I seem to be able to input 1-3/4", but cannot input 2’-6". Do I have to put 2.5’?
I’m really interested in moving over to Rhino, as I have been doing a lot of my 3D in sketchup where it very easy to input this info, any help would be appreciated.

type 2’6
not 2’-6"

the hyphen is used to separate inches from fractional inches

Thank you