[NTG-context] \math or $ doesn't work.

I want to insert the string 8 1/2 x 11 in my text. Here is my test file: ---------------------------- \starttext \math{8^1_2} × 11 inch, \stoptext ---------------------------- I am using texlive 2014 mkiv. -- John Culleton Wexford Press Book layout, typesetting and Indexing Free list of books for self-publishers: http://wexfordpress.net/shortlist.html