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

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

1  –  \addtocounter

  \addtocounter {counter} {value}

  The \addtocounter command increments the counter by the amount
  specified by the value argument.  The value argument can be negative.

2  –  \alph

  \alph {counter}

  This command causes the value of the counter to be printed in
  alphabetic characters.  The \alph command causes lower case
  alphabetic characters, e.g.  a, b, c...  while the \Alph command
  causes upper case alphabetic characters, e.g.  A, B, C...

3  –  \arabic

  \arabic {counter}

  The \arabic command causes the value of the counter to be printed in
  arabic numbers, e.g.  3.

4  –  \fnsymbol

  \fnsymbol {counter}

  The \fnsymbol command causes the value of the counter to be printed
  in a specific sequence of nine symbols that can be used for numbering
  footnotes.

5  –  \newcounter

  \newcounter {foo} [counter]

  The \newcounter command defines a new counter named foo.  The
  optional argument [counter] causes the counter foo to be reset
  whenever the counter named in the optional argument is incremented.

6  –  \roman

  \roman {counter}

  This command causes the value of the counter to be printed in roman
  numerals.  The \roman command causes lower case roman numerals, e.g.
  i, ii, iii..., while the \Roman command causes upper case roman
  numerals, e.g.  I, II, III...

7  –  \setcounter

  \setcounter {counter} {value}

  The \setcounter command sets the value of the counter to that
  specified by the value argument.

8  –  \usecounter

  \usecounter {counter}

  The \usecounter command is used in the second argument of the list
  environment to allow the counter specified to be used to number the
  list items.

9  –  \value

  \value {counter}

  The \value command produces the value of the counter named in the
  mandatory argument.  It can be used where LaTeX expects an integer or
  number, such as the second argument of a \setcounter or \addtocounter
  command, or in

  \hspace{\value{foo}\parindent}

  It is useful for doing arithmetic with counters.