I've got a fraction done this way in an org file:

\[
 \frac{1}{(2^3)(5)}
 \]

and I'd like to strike though or cancel the (5) part. The Latex method I've
found says do it this way:

...
\usepackage[makeroom]{cancel}
...

\[
 \frac{1}{(2^3)\cancel{(5)}}
 \]

But it's ignored and comes back verbatim. Of course +(5)+ doesn't work
either, again, coming back verbatim with the pluses. How can I do this?

LB