How do I create a LCM tree diagram?

Question

I am trying to create a LCM tree diagram which looks something like this:

Also what is the code to draw circles around numbers?

Answer 1

With my tikz-based package forest, this can be achieved in a very concise way:

\documentclass{article}
\usepackage{forest}
\begin{document}
\begin{forest} mark/.style={circle,draw=red}
  [8[2,mark][4[2,mark][2,mark]]]
\end{forest}
\end{document}

Answer 2

Tikz can do nice trees:

\documentclass{article}
\usepackage{tikz}

\begin{document}

\begin{center}
  \begin{tikzpicture}[thick]
    \node {8} 
    child { node[circle,draw=red] {2} }
    child { node {4} 
      child { node[circle,draw=red] {2} }
      child { node[circle,draw=red] {2} }
    };
  \end{tikzpicture}
\end{center}

\end{document}

Answer 3

Just to add the obligatory tikz-qtree solution:

\documentclass{article}
\usepackage{tikz-qtree}
\begin{document}
\begin{tikzpicture}[Red/.style={circle,draw=red}]
\Tree [.8 [.\node[Red] (A){2}; ]
          [.4 
            [.\node [Red] (B) {2}; ]
            [.\node [Red] (C) {2};]]]
\end{tikzpicture}
\end{document}