In To Kill a Mockingbird, what did Atticus mean when he told Scout to delete the adjective and she would have the facts?

In this line from Chapter 7, Atticus is not being
literal.  He is using figurative speech in an attempt to tell Scout to ignore the way
that Jem is exaggerating his accounts of how school gets to be more interesting as you
get older.

In this passage, Scout is unhappy because she
thinks second grade is "grim."  Jem does not really help -- he says that you don't learn
anything that's any good until you get to sixth grade.  At this point, Atticus tells
Scout to delete the adjectives.  What he means is that Jem is exaggerating -- school is
not really pointless until sixth grade.  But, at the same time, once you get past the
exaggeration, there is a kernel of truth -- school does get more interesting, he says,
as you get older.