newbie needing help getting started

[Juan Backson]

Hi,

I am following the tutorial trying to get started.  I am getting error with
the following sample code in ERL command line.

10> -module(math1).
** exception error: undefined shell command module/1
11> -export([factorial/1]).
** exception error: bad argument in an arithmetic expression
     in operator  '/'/2
        called as factorial / 1


Could someone help me out ?  What is wrong ?

jb