Aligning array elements horizontally LaTeX

Question

I'm trying to build a graphic illustration of how a binary multiplication is solved, but I'm facing some problems while trying to align the cells of the array. Here's the code:

\begin{array}{rrrrrr}
    &&1&1&0 & * \\
    &&&1&1 & = \\
\end{array}\newline
\rule{0.25\textwidth}{0.4pt}\\
\begin{array}{rrrrrr}
    &&1&1&0 &  \\
    &1&1&0&- &  \\
\end{array}\newline
\rule{0.25\textwidth}{0.4pt}\\
\begin{array}{rrrrrr}
    1&0&0&1&0_2 \\
\end{array}\newline

And here's the result:

Answer 1

You should use only one {array}.

\documentclass{article}
\usepackage{amsmath}
\usepackage{array}

\begin{document}

$\begin{array}{@{}cccccc@{}}
  &   & 1 & 1 & 0  & * \\
  &   &   & 1 & 1  & = \\ \hline
  &   & 1 & 1 & 0 \\
  & 1 & 1 & 0 & \text{--} \\ \hline
1 & 0 & 0 & 1 & 0_2 \\
\end{array}$

\end{document}