# help with section/equation numbering in amsbook

I am having trouble numbering chapters, equations, and sections in a coherent way in the amsbook class. I would like sections to be numbered according to chapters, e.g.

Chapter 1

Section 1.1

Subsection 1.1.1

equation 1.1

equation 1.2

equation 1.3....

...

Chapter 2

Section 2.1

Subsection 2.1.1

equation 2.1..

Right now I am using the preamble

\documentclass[oneside]{amsbook}
\usepackage[british]{babel}

\renewcommand{\thesection}{\thechapter.\arabic{section}}

\usepackage{chngcntr}
\counterwithout{section}{chapter}
\numberwithin{equation}{chapter}


and this numbers equations coherently within chapters, but not subsections. I can't figure out how to change it. If anyone has any comments (or suggestions on a better alternative) it would be much appreciated.

Thanks a lot.

You don't want to remove the section counter from the reset list of chapter.

\documentclass[oneside]{amsbook}
\usepackage[british]{babel}

\usepackage{chngcntr}
% remove equation from the reset list of section
\counterwithout*{equation}{section}
% add equation to the reset list of chapter
\counterwithin{equation}{chapter}

\begin{document}

\chapter{Chapter 1}

\section{Section 1.1}

\subsection{Subsection 1.1.1}

\begin{gather}
equation 1.1\\
equation 1.2\\
equation 1.3
\end{gather}

\section{Section 1.2}

\begin{gather}
equation 1.4\\
equation 1.5\\
equation 1.6
\end{gather}

\chapter{Chapter 2}

\section{Section 2.1}

\subsection{Subsection 2.1.1}

$$equation 2.1$$

\end{document}


The * forms of \counterwithin and \counterwithout don't change the representation of the counter they act on.