\begin{array}{col1col2...coln}
  column 1 entry & column 2 entry ... & column n entry \\
  .
  .
  .
  \end{array}

  Math arrays are produced with the array environment.  It has a single
  mandatory argument describing the number of columns and the alignment
  within them.  Each column, coln, is specified by a single letter that
  tells how items in that row should be formatted.

   -  c for centered

   -  l for flushleft

   -  r for flushright

  Column entries must be separated by an &.  Column entries may include
  other LaTeX commands.  Each row of the array must be terminated with
  a \\.