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 some of the counters used in LaTeX's standard document styles to control
numbering.
Counters are printed in LaTeX by using a command generated as
"\the" suffixed with the name of the counter. Thus, equation
numbers are printed by the \theequation command, and
section numbers by the \thesection command.
If you want to change the way such numbers are printed, for example,
change from arabic to Roman numerals, you need to redefine the
appropriate command, using the
\renewcommand command.
As an example, to number equations in an appendix as A-1,
A-2, ... , use
The second argument implies that the text produced by the renewed
\theequation command will be "A-" followed by the output from
the \arabic{equation} command, which is the value of the
equation counter, printed as an arabic number.
In List Environments the format for the
item labels is given by commands like \labelitemi and
\labelitemii (for the first two levels of the
Itemize Environment), and like \labelenumi
(for the Enumerate Environment), and these may
also be redefined.