Those are European sizes.....
I wear a 37/8 which is a size 7/8 ladies American size.
I don't know where you are but most sports stores in Canada that carry roller blades are fortunate enough to have them labelled with both the Canadian/American size and the European size........
When are you going?
I'm ill at home with a cold right now but I have to go to the Dr's tomorrow (I think it's pnuemonia) and I could check and see if I could find out for you.....