Counters

This information is obtained from the Info manual of LaTeX.

Everything LaTeX numbers for you has a counter associated with it. The name of the counter is the same as the name of the environment or command that produces the number, except with no backslash, \.

Below is a list of the counters used in LaTeX's standard document classes to control numbering.

 part            paragraph       figure          enumi
 chapter         subparagraph    table           enumii
 section         page            footnote        enumiii
 subsection      equation        mpfootnote      enumiv
 subsubsection

(enumi - enumiv are used for the nested enumerate environment)

These are some of the commands that refer to counters.
See examples in the sections Numbering and Fancy Stuff.

\alph: Print value of a counter using lower case letters.
\Alph: Print value of a counter using capital letters.
\arabic: Print value of a counter using numerals.
\roman: Print value of a counter using roman lower case numerals.
\Roman: Print value of a counter using roman capital numerals.
\fnsymbol: Print value of a counter using symbols.
\newcounter: Define a new counter.
\addtocounter: Add a quantity to a counter.
\refstepcounter: Add to counter, resetting subsidiary counters.
\setcounter: Set the value of a counter.
\stepcounter: Add to counter, resetting subsidiary counters.
\usecounter: Use a specified counter in a list environment.
\value: Use the value of a counter in an expression.

Here is an example:

  \renewcommand{\theequation}{\thesection.\arabic{equation}}

It redefines the macro \theequation, used to number equations, to produce section number, followed by a period, and the equation number in "arabic". A better way to achieve the same result is \numberwithin{equation}{section}. See more at Numbering.