答案1
这里没有什么特别花哨的东西,只有节点和巧妙的布局。可能可以用树来做,但如果你只有那些小东西要做……
\documentclass[tikz,border=3.14mm]{standalone}
\usetikzlibrary{positioning}
\begin{document}
\begin{tikzpicture}[
node distance=5mm,
every node/.style={inner xsep=0pt}]
\node (A) {$6$};
\node[below = of A,anchor=40] (B) {$4+5$};
\draw[->] (A) -- (A|-B.north);
\draw (B.south west) -- (B.south east);
\node[below= of B, anchor=40] (C) {$2+3$};
\draw[->] (B) -- (B|-C.north);
\draw (C.south west) -- (C.south east);
\node[below= of C,anchor=north] (D) {$1$};
\draw[->] (C) -- (D);
\end{tikzpicture}
\begin{tikzpicture}[
node distance=8mm,
every node/.style={inner xsep=0pt}]
\node (A) {$11+12+13$};
\draw (A.south west) -- (A.south east);
\node[below right = of A] (C) {$10$};
\node[above right = of C] (B) {$9$};
\draw[->] (A) -- (C.north west);
\draw[->] (B.south) -- (C.north east);
\node[below= of C] (D) {$8$};
\draw[->] (C) -- (D);
\end{tikzpicture}
\end{document}