There is a rule for comparisons using 'less' and 'fewer' in
which less is used with mass nouns and fewer is used with plural nouns.
(Ref. http://www.bartleby.com/68/20/3620.html)
Does the same rule apply to the greater or more comparisons? For
instance, would it be "More than 20 people" and "Greater than 20
cars"?
Or, can 'greater than' and 'more than' be used interchangeably?
Thanks