displaymath
\begin{displaymath} math \end{displaymath}
or
\[math\]
The displaymath
environment (\[...\]
is a synonym)
typesets the math text on its own line, centered by default.
The global fleqn
option makes equations flush left; see
Document class options.
No equation number is added to displaymath
text; to get an
equation number, use the equation
environment (see equation).