moodle/lang/it/help/coursenumsections.html

<P ALIGN=CENTER><B>Course Number of Weeks/Topics</B></P>

<P>This setting is only used by the 'weekly' and 'topics'
   course formats.

<P>In the 'weekly' format, it specifies the number of weeks 
   that the course will run for, starting from the 
   course starting date.

<P>In the 'topics' format, it specifies the number of topics
   in the course.

<P>Both of these translate to the number of "boxes" down the 
   middle of the course page.