LaTeX Counters and Numbering

\documentclass{article}
\begin{document}

% Display current counter values
Current page: \thepage

Current section: \thesection

Current figure: \thefigure

Current table: \thetable

% Show counter values in different formats
Page (arabic): \arabic{page}

Section (roman): \roman{section}

Chapter (Roman): \Roman{chapter}

\end{document}

\documentclass{article}
\begin{document}

% View current value
Current page counter: \thepage

% Set counter to specific value
\setcounter{page}{5}
New page value: \thepage

% Add to counter
\addtocounter{page}{3}
After adding 3: \thepage

% Step counter (increment by 1)
\stepcounter{page}
After stepping: \thepage

% Reset counter to zero
\setcounter{page}{0}
After reset: \thepage

\end{document}

\documentclass{article}

% Create new counters
\newcounter{example}
\newcounter{problem}
\newcounter{solution}

% Create counter that resets with another
\newcounter{subproblem}[problem]

\begin{document}

% Use custom counters
\stepcounter{example}
Example \theexample: This is the first example.

\stepcounter{example}
Example \theexample: This is the second example.

\stepcounter{problem}
Problem \theproblem: Solve this equation.

\stepcounter{subproblem}
Subproblem \theproblem.\thesubproblem: First part.

\stepcounter{subproblem}
Subproblem \theproblem.\thesubproblem: Second part.

\stepcounter{problem}
Problem \theproblem: New problem resets subproblem.

\stepcounter{subproblem}
Subproblem \theproblem.\thesubproblem: Starts at 1 again.

\end{document}

\documentclass{article}

\newcounter{demo}

% Redefine how counter is displayed
\renewcommand{\thedemo}{\Roman{demo}}

\begin{document}

% Default arabic format
\stepcounter{demo}
Demo \thedemo

% Change to alphabetic
\renewcommand{\thedemo}{\Alph{demo}}
\stepcounter{demo}
Demo \thedemo

% Change to roman numerals
\renewcommand{\thedemo}{\roman{demo}}
\stepcounter{demo}
Demo \thedemo

% Custom format with prefix/suffix
\renewcommand{\thedemo}{Example-\arabic{demo}}
\stepcounter{demo}
Demo \thedemo

% Complex format combining counters
\newcounter{chapter}
\newcounter{section}[chapter]
\renewcommand{\thesection}{\thechapter.\arabic{section}}

\setcounter{chapter}{3}
\stepcounter{section}
Section \thesection

\end{document}

\documentclass{article}
\usepackage{ifthen}

\newcounter{task}
\newcounter{step}

% Custom reset behavior
\newcommand{\newtask}{%
  \stepcounter{task}%
  \setcounter{step}{0}%
  \textbf{Task \thetask:}%
}

\newcommand{\newstep}{%
  \stepcounter{step}%
  \ifthenelse{\value{step}=1}%
    {Step \thestep:}%
    {Step \thestep:}%
}

\begin{document}

\newtask
\newstep First step of first task.
\newstep Second step of first task.

\newtask
\newstep First step of second task.
\newstep Second step of second task.
\newstep Third step of second task.

\end{document}

\documentclass{book}

% Create hierarchical counters
\newcounter{exercise}[chapter]
\newcounter{question}[exercise]
\newcounter{part}[question]

% Define display formats
\renewcommand{\theexercise}{\thechapter.\arabic{exercise}}
\renewcommand{\thequestion}{\theexercise.\arabic{question}}
\renewcommand{\thepart}{\thequestion(\alph{part})}

% Commands for easy use
\newcommand{\exercise}{%
  \stepcounter{exercise}%
  \setcounter{question}{0}%
  \textbf{Exercise \theexercise}%
}

\newcommand{\question}{%
  \stepcounter{question}%
  \setcounter{part}{0}%
  \par\textbf{Question \thequestion:}%
}

\newcommand{\part}{%
  \stepcounter{part}%
  \par(\thepart)%
}

\begin{document}

\chapter{Linear Algebra}

\exercise
\question What is a vector?
\part Define vector space.
\part Give three examples.

\question How do you add vectors?
\part Component-wise addition.
\part Geometric interpretation.

\exercise
\question What is a matrix?

\chapter{Calculus}

\exercise
\question What is a derivative?

\end{document}

\documentclass{article}

% Create counter for custom environment
\newcounter{theorem}[section]
\newcounter{lemma}[section]
\newcounter{corollary}[section]

% Define display format
\renewcommand{\thetheorem}{\thesection.\arabic{theorem}}
\renewcommand{\thelemma}{\thesection.\arabic{lemma}}
\renewcommand{\thecorollary}{\thesection.\arabic{corollary}}

% Create environments
\newenvironment{theorem}[1][]
{%
  \stepcounter{theorem}%
  \textbf{Theorem \thetheorem}%
  \ifthenelse{\equal{#1}{}}{}{ (#1)}%
  \textbf{.} \itshape%
}
{%
  \par\medskip%
}

\newenvironment{lemma}[1][]
{%
  \stepcounter{lemma}%
  \textbf{Lemma \thelemma}%
  \ifthenelse{\equal{#1}{}}{}{ (#1)}%
  \textbf{.} \itshape%
}
{%
  \par\medskip%
}

\begin{document}

\section{Basic Theory}

\begin{theorem}[Fundamental Theorem]
This is an important theorem in the first section.
\end{theorem}

\begin{lemma}
A supporting lemma for the theorem.
\end{lemma}

\begin{theorem}
Another theorem in the same section.
\end{theorem}

\section{Advanced Topics}

\begin{theorem}
New section resets the counter.
\end{theorem}

\end{document}

\documentclass{article}

% Create shared counter for all theorem-like environments
\newcounter{theorem}[section]

% All environments share the same counter
\newenvironment{theorem}[1][]
{%
  \stepcounter{theorem}%
  \textbf{Theorem \thesection.\arabic{theorem}}%
  \ifthenelse{\equal{#1}{}}{}{ (#1)}%
  \textbf{.} \itshape%
}{\par\medskip}

\newenvironment{lemma}[1][]
{%
  \stepcounter{theorem}%
  \textbf{Lemma \thesection.\arabic{theorem}}%
  \ifthenelse{\equal{#1}{}}{}{ (#1)}%
  \textbf{.} \itshape%
}{\par\medskip}

\newenvironment{corollary}[1][]
{%
  \stepcounter{theorem}%
  \textbf{Corollary \thesection.\arabic{theorem}}%
  \ifthenelse{\equal{#1}{}}{}{ (#1)}%
  \textbf{.} \itshape%
}{\par\medskip}

\begin{document}

\section{Mathematical Results}

\begin{theorem}
First result.
\end{theorem}

\begin{lemma}
Supporting lemma numbered consecutively.
\end{lemma}

\begin{corollary}
Follows from the theorem.
\end{corollary}

\begin{theorem}
Fourth result in the sequence.
\end{theorem}

\end{document}

\documentclass{article}
\usepackage{enumitem}

% Create custom counter for special lists
\newcounter{priority}
\renewcommand{\thepriority}{P-\arabic{priority}}

% Define custom list
\newlist{prioritylist}{enumerate}{1}
\setlist[prioritylist]{%
  label=\stepcounter{priority}\thepriority:,
  ref=\thepriority
}

\begin{document}

\section{Project Tasks}

\begin{prioritylist}
\item High importance task
\item Medium importance task  
\item Low importance task
\end{prioritylist}

\section{Requirements}

\begin{prioritylist}[resume]
\item Continue numbering from previous list
\item Another requirement
\end{prioritylist}

% Reset counter for new project
\setcounter{priority}{0}

\section{New Project}

\begin{prioritylist}
\item First task of new project
\item Second task of new project
\end{prioritylist}

\end{document}

\documentclass{article}
\usepackage{enumitem}

% Create counters for hierarchical numbering
\newcounter{requirement}
\newcounter{subrequirement}[requirement]
\newcounter{detail}[subrequirement]

% Define display formats
\renewcommand{\therequirement}{R\arabic{requirement}}
\renewcommand{\thesubrequirement}{\therequirement.\arabic{subrequirement}}
\renewcommand{\thedetail}{\thesubrequirement.\alph{detail}}

% Custom environments
\newenvironment{requirements}
{\begin{enumerate}[label=\stepcounter{requirement}\therequirement:]}
{\end{enumerate}}

\newenvironment{subrequirements}
{\begin{enumerate}[label=\stepcounter{subrequirement}\thesubrequirement:]}
{\end{enumerate}}

\newenvironment{details}
{\begin{enumerate}[label=\stepcounter{detail}\thedetail)]}
{\end{enumerate}}

\begin{document}

\section{System Requirements}

\begin{requirements}
\item User Authentication
  \begin{subrequirements}
  \item Login functionality
    \begin{details}
    \item Username validation
    \item Password encryption
    \item Session management
    \end{details}
  \item Registration process
    \begin{details}
    \item Email verification
    \item Data validation
    \end{details}
  \end{subrequirements}

\item Data Management
  \begin{subrequirements}
  \item Database design
  \item Backup procedures
  \end{subrequirements}
\end{requirements}

\end{document}

\documentclass{article}

\newcounter{definition}[section]
\renewcommand{\thedefinition}{\thesection.\arabic{definition}}

\newenvironment{definition}[1][]
{%
  \stepcounter{definition}%
  \textbf{Definition \thedefinition}%
  \ifthenelse{\equal{#1}{}}{}{ (#1)}%
  \textbf{.} \itshape%
}
{\par\medskip}

\begin{document}

\section{Basic Concepts}

\begin{definition}[Vector Space]\label{def:vector-space}
A vector space is a collection of objects called vectors.
\end{definition}

\begin{definition}[Linear Independence]\label{def:linear-independence}
Vectors are linearly independent if no vector can be written as a linear combination of the others.
\end{definition}

\section{Applications}

In Definition~\ref{def:vector-space}, we established the concept of vector spaces. Building on Definition~\ref{def:linear-independence}, we can now discuss bases.

The relationship between Definition~\ref{def:vector-space} and Definition~\ref{def:linear-independence} is fundamental to linear algebra.

\end{document}

\documentclass{article}

% Create index counter system
\newcounter{item}
\newcounter{subitem}[item]

\renewcommand{\theitem}{\arabic{item}}
\renewcommand{\thesubitem}{\theitem.\arabic{subitem}}

% Commands for index entries
\newcommand{\indexitem}[2]{%
  \stepcounter{item}%
  \setcounter{subitem}{0}%
  \textbf{\theitem. #1} \dotfill #2\par%
}

\newcommand{\indexsubitem}[2]{%
  \stepcounter{subitem}%
  \quad\textbf{\thesubitem} #1 \dotfill #2\par%
}

\begin{document}

\section{Index}

\indexitem{Introduction}{Page 1}
\indexsubitem{Overview}{Page 1}
\indexsubitem{Scope}{Page 2}
\indexsubitem{Methodology}{Page 3}

\indexitem{Theory}{Page 5}
\indexsubitem{Basic Concepts}{Page 5}
\indexsubitem{Advanced Topics}{Page 8}

\indexitem{Applications}{Page 12}
\indexsubitem{Example 1}{Page 12}
\indexsubitem{Example 2}{Page 15}
\indexsubitem{Case Studies}{Page 18}

\end{document}

\documentclass{article}

% Legal document counter system
\newcounter{article}
\newcounter{section}[article]
\newcounter{subsection}[section]
\newcounter{paragraph}[subsection]

% Custom display formats
\renewcommand{\thearticle}{\Roman{article}}
\renewcommand{\thesection}{\arabic{section}}
\renewcommand{\thesubsection}{\alph{subsection}}
\renewcommand{\theparagraph}{\roman{paragraph}}

% Commands for legal structure
\newcommand{\legalArticle}[1]{%
  \stepcounter{article}%
  \setcounter{section}{0}%
  \textbf{ARTICLE \thearticle}\par%
  \textbf{#1}\par\medskip%
}

\newcommand{\legalSection}[1]{%
  \stepcounter{section}%
  \setcounter{subsection}{0}%
  \textbf{Section \thearticle.\thesection.} #1\par%
}

\newcommand{\legalSubsection}[1]{%
  \stepcounter{subsection}%
  \setcounter{paragraph}{0}%
  \textbf{(\thesubsection)} #1\par%
}

\newcommand{\legalParagraph}[1]{%
  \stepcounter{paragraph}%
  \textbf{(\theparagraph)} #1\par%
}

\begin{document}

\legalArticle{GENERAL PROVISIONS}

\legalSection{Definitions}
\legalSubsection{In this document, unless the context otherwise requires:}
\legalParagraph{"Company" means the organization defined herein;}
\legalParagraph{"Agreement" refers to this contract;}
\legalParagraph{"Party" means any signatory to this agreement.}

\legalSection{Scope of Application}
\legalSubsection{This agreement applies to all parties involved.}

\legalArticle{TERMS AND CONDITIONS}

\legalSection{Obligations}
\legalSubsection{Each party shall:}
\legalParagraph{Fulfill their contractual obligations;}
\legalParagraph{Maintain confidentiality;}
\legalParagraph{Report any violations.}

\end{document}

\documentclass{article}

% Scientific numbering system
\newcounter{hypothesis}
\newcounter{experiment}
\newcounter{observation}[experiment]
\newcounter{conclusion}

\renewcommand{\thehypothesis}{H\arabic{hypothesis}}
\renewcommand{\theexperiment}{E\arabic{experiment}}
\renewcommand{\theobservation}{\theexperiment.\arabic{observation}}
\renewcommand{\theconclusion}{C\arabic{conclusion}}

% Scientific environments
\newenvironment{hypothesis}[1][]
{%
  \stepcounter{hypothesis}%
  \textbf{Hypothesis \thehypothesis}%
  \ifthenelse{\equal{#1}{}}{}{ (#1)}%
  \textbf{:} \itshape%
}{\par\medskip}

\newenvironment{experiment}[1][]
{%
  \stepcounter{experiment}%
  \setcounter{observation}{0}%
  \textbf{Experiment \theexperiment}%
  \ifthenelse{\equal{#1}{}}{}{ (#1)}%
  \textbf{:}%
}{\par\medskip}

\newenvironment{observation}[1][]
{%
  \stepcounter{observation}%
  \textbf{Observation \theobservation}%
  \ifthenelse{\equal{#1}{}}{}{ (#1)}%
  \textbf{:} \itshape%
}{\par\medskip}

\begin{document}

\section{Research Methodology}

\begin{hypothesis}[Primary]
Increased temperature will accelerate the reaction rate.
\end{hypothesis}

\begin{hypothesis}[Secondary] 
Pressure changes will have minimal effect on the reaction.
\end{hypothesis}

\begin{experiment}[Temperature Study]
Conduct reaction at various temperatures.

\begin{observation}[25°C]
Reaction completed in 60 minutes.
\end{observation}

\begin{observation}[50°C]
Reaction completed in 30 minutes.
\end{observation}

\begin{observation}[75°C]
Reaction completed in 15 minutes.
\end{observation}
\end{experiment}

\begin{experiment}[Pressure Study]
Conduct reaction at various pressures.

\begin{observation}[1 atm]
Reaction rate unchanged from baseline.
\end{observation}

\begin{observation}[2 atm]
Minimal change in reaction rate.
\end{observation}
\end{experiment}

\end{document}

\documentclass{report}

% Professional counter hierarchy
\newcounter{requirement}[chapter]
\newcounter{subrequirement}[requirement]
\newcounter{specification}[chapter]
\newcounter{testcase}[specification]

% Clear numbering formats
\renewcommand{\therequirement}{\thechapter.\arabic{requirement}}
\renewcommand{\thesubrequirement}{\therequirement.\arabic{subrequirement}}
\renewcommand{\thespecification}{\thechapter.\arabic{specification}}
\renewcommand{\thetestcase}{\thespecification.\arabic{testcase}}

% Consistent formatting commands
\newcommand{\Requirement}[1]{%
  \stepcounter{requirement}%
  \setcounter{subrequirement}{0}%
  \paragraph{Requirement \therequirement:} #1%
}

\newcommand{\SubRequirement}[1]{%
  \stepcounter{subrequirement}%
  \subparagraph{Requirement \thesubrequirement:} #1%
}

\newcommand{\Specification}[1]{%
  \stepcounter{specification}%
  \setcounter{testcase}{0}%
  \paragraph{Specification \thespecification:} #1%
}

\newcommand{\TestCase}[1]{%
  \stepcounter{testcase}%
  \subparagraph{Test Case \thetestcase:} #1%
}

\begin{document}

\chapter{User Interface Requirements}

\Requirement{The system shall provide a user-friendly interface.}
\SubRequirement{All buttons shall be clearly labeled.}
\SubRequirement{Navigation shall be intuitive.}

\Requirement{The interface shall be responsive.}
\SubRequirement{Layout shall adapt to screen size.}

\Specification{Login form implementation}
\TestCase{Valid credentials acceptance}
\TestCase{Invalid credentials rejection}

\Specification{Menu navigation implementation}
\TestCase{Menu accessibility}
\TestCase{Submenu functionality}

\chapter{Performance Requirements}

\Requirement{Response times shall be minimal.}
\SubRequirement{Page loads under 2 seconds.}
\SubRequirement{Database queries under 1 second.}

\end{document}

\documentclass{article}

% Problem: Counter not resetting properly
% Solution: Ensure proper counter dependency

\newcounter{main}
\newcounter{sub}[main]  % Correctly reset sub when main increments

% Problem: Wrong display format
% Solution: Check \renewcommand{\thecounter}

\renewcommand{\themain}{\arabic{main}}  % Correct format
\renewcommand{\thesub}{\themain.\arabic{sub}}

% Problem: Counter value not updating
% Solution: Use \stepcounter or \addtocounter

\newcommand{\newmain}{%
  \stepcounter{main}%  % Correct: increments counter
  % \setcounter{main}{\value{main}+1}  % Wrong: doesn't work
}

% Problem: References showing wrong number
% Solution: Ensure counter is stepped before labeling

\newcommand{\labeleditem}[1]{%
  \stepcounter{main}%  % Step BEFORE label
  \label{#1}%
  Item \themain%
}

\begin{document}

\newmain
Main item \themain

\stepcounter{sub}
Sub item \thesub

\newmain
Next main item (sub resets): \themain, \thesub

\labeleditem{item:first}
This can be referenced as \ref{item:first}.

\end{document}