Creating a strikeout command

Question

I am trying to create a command that works in mathmode which simulates a strikeout diagonally while leaving the math display intact.

\documentclass{article}
\usepackage{amsmath,amssymb}
\usepackage[dvipsnames]{xcolor}
\usepackage{tikz}
\usetikzlibrary{shapes.misc}

\newcommand{\tikzmark}[1]{\tikz[overlay,remember picture] \node (#1) {};}
\newcommand{\strikeout}[1]{%
\ifmmode%
      \tikz[inner sep=0.5pt,baseline] \node [strike out,draw=OrangeRed,anchor=text]{$#1$};%
\else%
      \tikz[inner sep=0.5pt,baseline] \node [strike out,draw=OrangeRed,anchor=text]{#1};%
\fi%
}

\begin{document}
$\dfrac{x^2\times 10^3}
{x^2\strikeout{\times 10^3}}$

$\dfrac{x^2\times 10^3}
{x^2\tikzmark{matha}\times 10^3\tikzmark{mathb}}$
\tikz[remember picture, overlay,OrangeRed]
{\draw ($(matha)+(0.1em,-0.125em)$) --
            ($(mathb)+(-0.1em,0.825em)$);}

$\dfrac{x^2\times 10^3}
{x^2\tikzmark{matha}\times 10^3\tikzmark{mathb}}$
\tikz[remember picture, overlay,OrangeRed,baseline]
{\draw[anchor=text] (matha.south west) --
            (mathb.north east);}
\end{document}

Note the discrepancies in the displays. The first does not maintain the mathmode. Note I want this to work for any scenario thus I was thinking of redefining the strikeout command I have by using remember picture, overlay. But note my problem is to get to the line to be drawn like the original strikeout command. The second code seems to do the trick but it is fixed and am trying to make a user friendly command and well the third, its just out of the question. Thus, I am looking for a suitable way to make a command usable and with the results desired.

Answer 1

As noted by cgnieder in comments you can restore the mathbin spacing of \times by inserting {} at the ends of the math mode list inside the node. The code below adds that to \strikeout used in the first example. However this still boxes the subexpression making a mathord out of the term and freezing any white space at its natural width.

If the tikz bits in the second example are doing anything like I think they are doing (which is not guaranteed) then instead the tikz marks are attached to the individual atoms so no subterm involving white space is boxed, and the spacing is re-asserted by making the combination of the first mark and the times a mathbin atom. With a bit more work the code could determine the class of its argument and insert \mathbin (or \mathxx) automatically.

\documentclass{article}
\usepackage{amsmath,amssymb}
\usepackage[dvipsnames]{xcolor}
\usepackage{tikz}
\usetikzlibrary{shapes.misc}
\newcommand{\tikzmarkb}[3]{\tikz[remember picture,baseline,inner sep=0pt] \node[anchor=text](#2) 
{$#1#3$};}

\newcommand{\strikeout}[1]{%
\ifmmode%
      \tikz[inner sep=0.5pt,baseline] \node [strike out,draw=OrangeRed,anchor=text]{${}#1{}$};%
\else%
      \tikz[inner sep=0.5pt,baseline] \node [strike out,draw=OrangeRed,anchor=text]{#1};%
\fi%
}

\begin{document}
$\dfrac{x^2\times 10^3}
{x^2\strikeout{\times 10^3}}$


\bigskip

$\dfrac{x^2\times 10^3}
{x^2\mathbin{\tikzmarkb{}{matha}\times} 10^{\tikzmarkb\scriptstyle{mathb}3}}$
\tikz[remember picture, overlay,OrangeRed,baseline]
{\draw[anchor=text] (matha.south west) --
            (mathb.north east);}
\end{document}