Dtyjlui

I want to write the mathematics inside the box as written below.

See my code given below:

documentclass{article}



begin{document}

\fbox{text}

framebox[width][pos]{text}



makebox[textwidth]{X_1 X_2} par

makebox[textwidth]{X_3 X_4} par

cdots

makebox[textwidth]{X_4 X_6} par



end{document}

Question: I want to write the above maths, How to write it properly?

You can use boxed command from amsmath package

documentclass{article}

usepackage{amsmath}

begin{document}



begin{equation*}

    X=boxed{X_1 X_2}quad boxed{X_3 X_4}cdotsboxed{X_5 X_6}

end{equation*}







end{document}

To add colors and labels below boxes

documentclass{article}

usepackage{amsmath,tcolorbox}

tcbuselibrary{theorems,skins}

usetikzlibrary{arrows.meta}



newlengthmylabelshift

setlengthmylabelshift{3mm} % to be adjusted if needed



newcommand{drawlabel}[1]{draw[Stealth-Stealth]([yshift=-mylabelshift]frame.south west)--node[fill=white]{(#1)}([yshift=-mylabelshift]frame.south east);}

newtcbox{mymathbox}[1][l]{

               enhanced,

               nobeforeafter,

               math upper,

               tcbox raise base,

               colback=blue!30, % to set background color

               size=small,

               geometry nodes,

               overlay={drawlabel{#1}},

               tcbox width=minimum center,

               width= 2 cm ,% to be adjusted if needed

               }

begin{document}



begin{equation*}

    X=mymathbox{X_1 X_2}quad mymathbox{X_3 X_4 X_5}cdotsmymathbox{X_5 X_6}

end{equation*}

vspace{1cm}

begin{equation*}

    X=mymathbox[a]{X_1 X_2}quad mymathbox[b]{X_3 X_4}cdotsmymathbox[c]{X_5 X_6}

end{equation*}





end{document}

Depends on how fancy you want to go. In principle you do not need any packages for that.

documentclass{article}

begin{document}

[

 X=

 raisebox{-1.5ex}{$begin{array}{c}

 hline

 multicolumn{1}{|c|}{X_1 X_2}\

 hline

 leftarrowellrightarrow\

 end{array}$}~

 raisebox{-1.5ex}{$begin{array}{c}

 hline

 multicolumn{1}{|c|}{X_3 X_4}\

 hline

 leftarrowellrightarrow\

 end{array}$}cdots

 raisebox{-1.5ex}{$begin{array}{c}

 hline

 multicolumn{1}{|c|}{X_5 X_6}\

 hline

 leftarrowellrightarrow\

 end{array}$}

]



end{document}

Here's a package-free version (amsmath is always needed if one does math).

documentclass{article}

usepackage{amsmath}



newcommand{block}[2]{%

  begin{array}[t]{@{}c@{}}

  boxed{mathstrut #1}\

  scriptstyleblockleftarrowfill,#2,blockrightarrowfill

  end{array}%

}

newcommand{blockleftarrowfill}{%

 mathordleftarrow

 mkern -7mu

 cleadershbox{$scriptstylemkern -2musmash-mkern -2mu$}hfill

 mkern -7musmash-%

}

newcommand{blockrightarrowfill}{%

  smash-%

  mkern -7mu

  cleadershbox{$scriptstylemkern -2musmash-mkern -2mu$}hfill

  mkern -7mu

  mathordrightarrow

}



begin{document}



[

X= block{x_1 x_2quad}{l}quad

   block{x_3 x_4quad}{l}quad

   cdotsquad

   block{x_5 x_6quad}{l}

]



end{document}