I'm currently trying to TeX up a Sieve of Eratosthenes example on the integers 2-100. I'm already using the ulem and cancel packages to give me horizontal and diagonal strikethroughs but I need a vertical strikethrough as well which would go through the same point as the horizontal and diagonal strikethroughs.
It doesn't have to be a general solution so one that works for 2-digit numbers in math-mode will suffice.
\documentclass[pdf]{beamer}
\usepackage{ulem}
\usepackage{cancel}
\newcommand{\strike}[1]{\text{\sout{$#1$}}}
\begin{document}
\begin{array}{c c c c c c c c c c}
& \cancel{2\:} & \strike{3\:} & \cancel{4\:} & \bcancel{5\:} & \strike{\cancel{6\:}} & 7\: & \cancel{8\:} & \strike{9\:} & \xcancel{10}\\
11 & \strike{\cancel{12}} & 13 & \cancel{14} & \bcancel{\strike{15}} & \cancel{16} & 17 & \strike{\cancel{18}} & 19 & \xcancel{20}\\
\strike{21} & \cancel{22} & 23 & \strike{\cancel{24}} & \bcancel{25} & \cancel{26} & \strike{27} & \cancel{28} & 29 & \strike{\xcancel{30}}\\
31 & \cancel{32} & \strike{33} & \cancel{34} & \bcancel{\textcolor{red}{35}} & \strike{\cancel{36}} & 37 & \cancel{38} & \strike{39} & \xcancel{40}\\
41 & \strike{\cancel{42}} & 43 & \cancel{44} & \bcancel{\strike{45}} & \cancel{46} & 47 & \strike{\cancel{48}} & 49 & \xcancel{50}\\
\strike{51} & \cancel{52} & 53 & \strike{\cancel{54}} & \bcancel{55} & \cancel{56} & \strike{57} & \cancel{58} & 59 & \strike{\xcancel{60}}\\
61 & \cancel{62} & \strike{63} & \cancel{64} & \bcancel{65} & \strike{\cancel{66}} & 67 & \cancel{68} & \strike{69} & \xcancel{\textcolor{red}{70}}\\
71 & \strike{\cancel{72}} & 73 & \cancel{74} & \bcancel{\strike{75}} & \cancel{76} & 77 & \strike{\cancel{78}} & 79 & \xcancel{80}\\
\strike{81} & \cancel{82} & 83 & \strike{\cancel{84}} & \bcancel{85} & \cancel{86} & \strike{87} & \cancel{88} & 89 & \strike{\xcancel{90}}\\
91 & \cancel{92} & 93 & \cancel{94} & \bcancel{95} & \strike{\cancel{96}} & 97 & \cancel{98} & \strike{99} & \xcancel{100}\\
\end{array}
\end{document}
What I'd like to do is add horizontal strikes to the multiples of 7 now but can't seem to do it nicely. I've tried using something like
\newcommand{\hstrike}[1]{\strike{#1}\!\mid}
or
\newcommand{\hstrike}[1]{| \! \strike{#1}}
But it screws up the rest of the formatting and that's not changed if I use \mkern instead of \!.

\documentclass{...}and ending with\end{document}. – cfr Jan 20 '15 at 02:44