I am from Europe and I do some research for my thesis. I found this picture, which is very usefull for me, but unfortunately the lengths are in imperial units (for lenght they are using something like this 7'-11.5''). I know, that this symbol: ' is for feet and this: '' is for inches. But I am little bit struggling with this notation. Is this interval (it doesn't make much sense if so) or it's x feets minus y inches?
Thanks for the answers, I know that this is lame question, but as European metric system user I am little bit confused :)