Number Equations and Figures by Sections or Subsections in LaTeX
May. 16, 2025 • Updated May. 16, 2025
(1) Number equations and figures by sections
In LaTeX, we can use commands:
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\numberwithin{equation}{section}
\numberwithin{figure}{section}
to number equations and figures by sections. Here is an example.
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\documentclass[a4paper]{article}
\usepackage[margin=1in]{geometry}
\usepackage{amsmath}
\usepackage[colorlinks, linkcolor=blue]{hyperref}
\usepackage[x11names]{xcolor}
\pagecolor{AntiqueWhite1}
\usepackage{graphicx,subfig}
\renewcommand{\figurename}{Fig.}
\numberwithin{equation}{section}
\numberwithin{figure}{section}
\def\CE{0.20}
\begin{document}
\section{Section 1}
\begin{figure}[h]
\centering
\subfloat[]{\includegraphics[height=\CE\textwidth,width=\CE\textwidth]{ctanlion.eps}\label{fig-a}}\hfill
\subfloat[]{\includegraphics[height=\CE\textwidth,width=\CE\textwidth]{ctanlion.eps}}\hfill
\subfloat[]{\includegraphics[height=\CE\textwidth,width=\CE\textwidth]{ctanlion.eps}}\hfill
\subfloat[]{\includegraphics[height=\CE\textwidth, width=\CE\textwidth]{ctanlion.eps}}
\caption{CTAN lion}
\label{fig-1}
\end{figure}
\begin{equation}
a=b+c\\
\end{equation}
\section{Section 2}
\begin{equation}
a=b+c\\
\end{equation}
\begin{figure}[h]
\centering
\subfloat[]{\includegraphics[height=\CE\textwidth,width=\CE\textwidth]{ctanlion.eps}\label{fig-a}}\hfill
\subfloat[]{\includegraphics[height=\CE\textwidth,width=\CE\textwidth]{ctanlion.eps}}\hfill
\subfloat[]{\includegraphics[height=\CE\textwidth,width=\CE\textwidth]{ctanlion.eps}}\hfill
\subfloat[]{\includegraphics[height=\CE\textwidth, width=\CE\textwidth]{ctanlion.eps}}
\caption{CTAN lion}
\label{fig-2}
\end{figure}
\subsection{Subsection 2.1}
\begin{equation}
a=b+c\\
\end{equation}
\begin{figure}[h]
\centering
\subfloat[]{\includegraphics[height=\CE\textwidth,width=\CE\textwidth]{ctanlion.eps}\label{fig-a}}\hfill
\subfloat[]{\includegraphics[height=\CE\textwidth,width=\CE\textwidth]{ctanlion.eps}}\hfill
\subfloat[]{\includegraphics[height=\CE\textwidth,width=\CE\textwidth]{ctanlion.eps}}\hfill
\subfloat[]{\includegraphics[height=\CE\textwidth, width=\CE\textwidth]{ctanlion.eps}}
\caption{CTAN lion}
\label{fig-3}
\end{figure}
\begin{equation}
a=b+c\\
\end{equation}
\subsection{Subsection 2.2}
\begin{equation}
a=b+c\\
\end{equation}
\begin{equation}
a=b+c\\
\end{equation}
\subsection{Subsection 2.3}
\begin{equation}
a=b+c\\
\end{equation}
\begin{figure}[h]
\centering
\subfloat[]{\includegraphics[height=\CE\textwidth,width=\CE\textwidth]{ctanlion.eps}\label{fig-a}}\hfill
\subfloat[]{\includegraphics[height=\CE\textwidth,width=\CE\textwidth]{ctanlion.eps}}\hfill
\subfloat[]{\includegraphics[height=\CE\textwidth,width=\CE\textwidth]{ctanlion.eps}}\hfill
\subfloat[]{\includegraphics[height=\CE\textwidth, width=\CE\textwidth]{ctanlion.eps}}
\caption{CTAN lion}
\label{fig-4}
\end{figure}
\begin{figure}[h]
\centering
\subfloat[]{\includegraphics[height=\CE\textwidth,width=\CE\textwidth]{ctanlion.eps}\label{fig-a}}\hfill
\subfloat[]{\includegraphics[height=\CE\textwidth,width=\CE\textwidth]{ctanlion.eps}}\hfill
\subfloat[]{\includegraphics[height=\CE\textwidth,width=\CE\textwidth]{ctanlion.eps}}\hfill
\subfloat[]{\includegraphics[height=\CE\textwidth, width=\CE\textwidth]{ctanlion.eps}}
\caption{CTAN lion}
\label{fig-5}
\end{figure}
\begin{equation}
a=b+c\\
\end{equation}
\section{Section 3}
\begin{figure}[h]
\centering
\subfloat[]{\includegraphics[height=\CE\textwidth,width=\CE\textwidth]{ctanlion.eps}\label{fig-a}}\hfill
\subfloat[]{\includegraphics[height=\CE\textwidth,width=\CE\textwidth]{ctanlion.eps}}\hfill
\subfloat[]{\includegraphics[height=\CE\textwidth,width=\CE\textwidth]{ctanlion.eps}}\hfill
\subfloat[]{\includegraphics[height=\CE\textwidth, width=\CE\textwidth]{ctanlion.eps}}
\caption{CTAN lion}
\label{fig-6}
\end{figure}
\begin{equation}
a=b+c\\
\end{equation}
\begin{equation}
a=b+c\\
\end{equation}
\end{document}
(2) Number equations and figures by subsections
Similarly, by subsections we could use commands:
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% ...
\numberwithin{equation}{subsection}
\numberwithin{figure}{subsection}
% ...
References