Why must you add five extra spaces to the right margin
when you are planning margin stops?  For many teachers this
is a tricky question to answer.  Here is a detailed step by
step answer to this question.  You do realize that you must
have a bell or other audible sound to warn you when you are
nearing the right edge of your paper.  Without this audible
signal you would have to visually scan your work to prevent
typing off the paper.  Your margin should be set at a point
that will result in your bell sounding exactly three spaces
to the left of what is considered the desired ending point.
     Thus, when your bell rings it is in effect warning you
that you have three typing spaces left before you reach the
desired carriage return point.  However, if a word is being
completed as the bell rings, the return is initiated before
the desired point; likewise, if the typist is in the middle
of a lengthy word as the bell rings, normally the word will
be completed and the return made at a point to the right of
the desired line ending.  On most typewriters the bell will
ring eight spaces before the margin stop; by adding five to
the right margin, the bell thus rings at the correct point.