strikethrough and cancellations

Newsgroups: comp.text.tex
> Is there any LaTeX command (or package) that implements a "strikethrough" or
> cancellation font attribute?
>
> For instance, if I have something like \frac{2}{2}, I would like to input
> this as \frac{\S{2}}{\S{2}}, where \S puts a forward slash on top of its
> argument, to show a cancellation. It's probably possible to do something
> with boxes but it would be ideal if there was a command that did this
> automatically (so that the spacing and size of the slash could be
> controlled).

I've never used it myself, but I think the "cancel" package on CTAN is supposed to do that.

Scott