# [texhax] Oblique cancellation with plain TeX

Fri Jan 4 21:30:23 CET 2019

On Fri, Jan  4, 2019 at 19:14 (+0000), Rodolfo Medina wrote:

> Philip Taylor <P.Taylor at Rhul.Ac.Uk> writes:

>> Maybe if you were to post a GIF/PNG/JPG/PDF of the effect you are trying to
>> create, we non-mathematicians might be better placed to help you ...

> The following is a simple example: to be processed with simply latex file'.  I
> want the same but with plain TeX...  Thanks,

> Rodolfo

> \documentclass[preview,border=12pt,varwidth]{standalone}
> \usepackage{cancel}
> \begin{document}
> \abovedisplayskip=0pt
> $> \frac{a\cancel{b}}{\cancel{b}}=a >$
> \end{document}

What is wrong with

$${a\rlap{b}/ \over \rlap{b}/} = a$$

(Aside from the fact that if $b = 0$ then Bad Things are happening?)

You could also write

\def\cancel#1{\rlap{$#1$}/}

somewhere near the beginning of your document and then, when you want
to cancel things out, write something like

$${a\cancel{b} \over \cancel{b}} = a$$

or

This is ${a\cancel{b} \over \cancel{b}} = a$ a simple idea.

Cheers.

Jim

`