Cancel package enhancement

Question

How difficult is it to enhance (=copy the code of the package in my project and adapt it) the Cancel package, Cancel package, with a command \cancelno{〈label〉}{〈expression〉} such that

• a slash is put on the underlying 〈expression〉 as by \cancel
• no arrow
• the number/text 〈label〉 is put on top of 〈expression〉 in the middle

the goal is to describe which term cancel with which term, this is useful if one has lets say 16 terms each cancelling with each other.

I think that the command \cancelto of the package should be a good model.

In the following MEW one should replace \cancelto with \cancelno and obtain the desired result.

\documentclass{article}
\usepackage{graphicx}
\usepackage{amsmath}
\usepackage{amsthm}
\usepackage{amsfonts}
\usepackage{cancel}
\begin{document}
\section{Something}

\begin{align*}
\left(\begin{bmatrix}a\\b\\c\end{bmatrix}
\times
\begin{bmatrix}x\\y\\z\end{bmatrix}\right)
\cdot\begin{bmatrix}a\\b\\c\end{bmatrix}
&=\begin{bmatrix}bz-cy\\cx-az\\ay-bx\end{bmatrix}
\cdot\begin{bmatrix}a\\b\\c\end{bmatrix}\\
&=\cancelto{1}{bza}-\cancelto{2}{cya}+\cancelto{3}{cxb}
-\cancelto{1}{azb}+\cancelto{2}{ayc}-\cancelto{3}{bxc}
\end{align*}

\end{document}

Answer 1

Presumably it is possible.

\documentclass{article}
\usepackage{amsmath}
\usepackage{cancel}
\newcommand{\mycancel}[2]{\overset{#1}{\cancel{#2}}}
\begin{document}
\section{Something}

\begin{align*}
\left(\begin{bmatrix}a\\b\\c\end{bmatrix}
\times
\begin{bmatrix}x\\y\\z\end{bmatrix}\right)
\cdot\begin{bmatrix}a\\b\\c\end{bmatrix}
&=\begin{bmatrix}bz-cy\\cx-az\\ay-bx\end{bmatrix}
\cdot\begin{bmatrix}a\\b\\c\end{bmatrix}\\
&=\mycancel{1}{bza}-\mycancel{2}{cya}+\mycancel{3}{cxb}
-\mycancel{1}{azb}+\mycancel{2}{ayc}-\mycancel{3}{bxc}
\end{align*}
\end{document}