Multiple columns in table

Question

I have this table below and I have been ever since trying to make the column work, but it just does not appear like this at all.

The first and the second column are fine, but when it comes to the fact that the 3rd and the 4th column splits into 4 sub columns gives a hard time.

Answer 1

I think you need to contemplate displaying your table in landscape mode, especially if you want to avoid having to resort to minuscule font sizes. In the code below, I use \allowbreak directives to introduce line breaks in some of the columns. I would also like to recommend (i) not using any vertical lines in the table and (ii) using the line-drawing macros of the booktabs package instead of \hline and \cline.

\documentclass[a4paper]{article}  % specify page size
\usepackage[margin=1in]{geometry} % specify text block size
\usepackage{rotating,tabularx,amssymb,ragged2e,booktabs}
\newcolumntype{C}{>{\Centering\arraybackslash}X}
\newcommand\swb{{\scriptstyle\Box}} % "small white box"
\begin{document}

\begin{sidewaystable}
\setlength\tabcolsep{2pt} % default value: 6pt
\begin{tabularx}{\textwidth}{@{}*{10}{C}@{}} 
\toprule
 $\delta_m$ & $2 \neq \swb$ & \multicolumn{4}{c}{$5 \cdot 29 \neq \swb$} & \multicolumn{4}{c}{$13 \cdot 1789 \neq \swb$} \\
\cmidrule(lr){3-6} \cmidrule(l){7-10}
    &   & $5=\swb$ & $29\neq\swb$ & $5\neq\swb$ & $29=\swb$ & $13=\swb$ & $1789\neq\swb$ & $13\neq\swb$ & $1789=\swb$ \\
\midrule
Primes that satisfy the condition $\delta_m \neq \swb$  & 
$q\equiv\pm3\pmod8$ & 
$q\equiv\pm1\pmod5$ & 
$q\equiv 2,3,8,10,\allowbreak11,12,14,15,\allowbreak17,18,19,21,\allowbreak26,27\pmod{29}$ & 
$q\equiv\pm2\pmod5$ & 
$q\equiv 1,4,5,6,\allowbreak7,9,13,16,20,\allowbreak22,23,24,25,\allowbreak28\pmod{29}$ & 
$q\equiv 1,3,4,9,\allowbreak10,12\pmod{13}$ & 
$q\equiv A\pmod{1789}$ & 
$q\equiv2,5,6,7,\allowbreak8,11\pmod{13}$ & 
$q\equiv B\pmod{1789}$ \\ 
\midrule
 Period of $w_n$  & $24$ & $30$ & $102$ & $30$ & $102$ & $30$ & $2670$ & $30$ & $2670$ \\
\bottomrule
\end{tabularx}
\end{sidewaystable}
\end{document}

Answer 2

It is the reverse actually: you should not split one column in to four columns, Use four columns and merge them in to one.

\documentclass[border=3pt]{standalone}
\begin{document}
\begin{tabular}{|*{10}{l|}} \hline
  1 & 2 & \multicolumn{4}{c|}{3 to 6} & \multicolumn{4}{c|}{7 to 10} \\\cline{3-10}
    &   & 3 & 4 & 5 & 6 & 7 & 8 & 9 & 10 \\\hline
  1 & 2 & 3 & 4 & 5 & 6 & 7 & 8 & 9 & 10 \\\hline
\end{tabular}
\end{document}

You can use tabularx as stated in comments below:

\documentclass{article}
\usepackage{pdflscape}
\usepackage{tabularx,array}
\begin{document}
\begin{landscape}
\begin{table}[htbp]
\begin{tabularx}{\textwidth}{|*{10}{X|}} \hline
  1 & 2 & \multicolumn{4}{c|}{3 to 6} & \multicolumn{4}{c|}{7 to 10} \\\cline{3-10}
    &   & 3 & 4 & 5 & 6 & 7 & 8 & 9 & 10 \\\hline
  1 & 2 & 3 & 4 & 5 & 6 & 7 & 8 & 9 & 10 \\\hline
\end{tabularx}
\end{table}
\end{landscape}
\end{document}