I'm trying to construct a diagram of how to calculate a 3x3 matrix determinant via the Rule of Sarrus, and I've managed to come this far after lots of research, but I still would like to make the arrows apear underneath the numbers, and the curved arrow to have a circled minus sign in the middle, unfortunately I have yet to find a way of doing this, so if someone can point me in the right direction I would very much appreciate.
This is the code I'm using, and the result bellow.
%preamble
\documentclass{article}
\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{bm}
\usepackage{circuitikz}
\usepackage{tikz}
\newcommand\tikznode[1]{\tikz[overlay,remember picture] \node (#1) {};}
\tikzset{>=latex}
------------
%document
\begin{equation*}
\left|\begin{matrix}
\tikznode{11}2& \tikznode{12}7 & \tikznode{13}6\\
\tikznode{21}9& \tikznode{22}5 & \tikznode{23}1\\
\tikznode{31}4& \tikznode{32}3 & \tikznode{33}8
\end{matrix}
\middle|\;\begin{matrix}
\tikznode{14}2& \tikznode{15}7\\
\tikznode{24}9& \tikznode{25}5\\
\tikznode{34}4& \tikznode{35}3
\end{matrix}\right| \qquad
\begin{matrix}
4*5*6+3*1*2+8*9*7 = 630\tikznode{top}\\
\\
\\
\\
2*5*8+7*1*4+6*9*3 = 270\tikznode{btn}
\end{matrix}\qquad \qquad
270-630 = -360
\begin{tikzpicture}[overlay, remember picture]
\foreach \i in {1,2,3}
\def\e{\the\numexpr\i+2}
\draw[->,red,line width=1pt] ($(1\i.north east)+(-0.5,0.5)$) -- ($(3\e.south west)+(0.6,-0.2)$);
\foreach \i in {3,4,5}
\def\e{\the\numexpr\i-2}
\draw[<-,blue,line width=1pt] ($(1\i.north west)+(0.7,0.5)$) -- ($(3\e.south east)+(-0.4,-0.2)$);
\path[->,line width=1pt] ($(btn)+(0.25,0)$) edge[bend right=60] ($(top)+(0.25,0)$);
\end{tikzpicture}
\end{equation*}
And the desired result is something along this lines (without the + and - signs ono top and bottom):