列举文档的一些章节

Question

摘要不要列举，目录从I开始（罗马数字），第一章从1开始（普通数字），怎么写？

\documentclass[11pt,letterpaper]{report}    
%\usepackage{etoolbox}
\usepackage{titlesec}

\begin{document}
{
\titleformat{\chapter}[block]{\filcenter\Huge\bfseries}{}{0pt}{}
\titlespacing{\chapter}{0pt}{0pt}{40pt}
\chapter*{ABSTRACT}
}

%\chapter*{\makebox[\linewidth]{ABSTRACT}}%\chapter*{\centering Abstract}
El principal mecanthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis intro

\section{Exp}
this Exp SECTION
\tableofcontents
\chapter{ETAPA2}
\label{cap:experimental}
this intro

\section{Exp2}
this Exp SECTION

\end{document}

Answer 1

基于https://tex.stackexchange.com/a/408118/36296你可以做这样的事情：

\documentclass[11pt,letterpaper]{report}    
%\usepackage{etoolbox}
\usepackage{titlesec}

\newcommand\frontmatter{%
  \cleardoublepage
  % \@mainmatterfalse
  \pagenumbering{roman}
}

\newcommand\mainmatter{%
    \cleardoublepage
    % \@mainmattertrue
    \pagenumbering{arabic}
  }

\newcommand\backmatter{%
  \if@openright
    \cleardoublepage
  \else
    \clearpage
  \fi
  % \@mainmatterfalse
}


\begin{document}

{
\titleformat{\chapter}[block]{\filcenter\Huge\bfseries}{}{0pt}{}
\titlespacing{\chapter}{0pt}{0pt}{40pt}
\chapter*{ABSTRACT}
}
\thispagestyle{empty}
%\chapter*{\makebox[\linewidth]{ABSTRACT}}%\chapter*{\centering Abstract}
El principal mecanthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis introthis intro

\section{Exp}
this Exp SECTION

\frontmatter
\tableofcontents

\mainmatter
\chapter{ETAPA2}
\label{cap:experimental}
this intro

\section{Exp2}
this Exp SECTION

\end{document}