One And One Is Two

Little Johnny was busy doing his homework.  As his mother approached she heard:
"One and one, the son-of-a-bitch is two.  Two and two, the son-of-a-bitch is
four.  Three and three... "

His mother interrupted, asking where he had learned this way of doing math.  
Johnny remarked that his teacher Ms. Clara Jones taught him.  His mother was
rather upset and told him to stop the homework.  The next day she approached
Ms. Jones and told her what happened.  

The teacher was flabbergasted.  She said that she couldn't understand why Johnny
had said what he did.  Then suddenly, Ms Jones exclaimed, "Oh, I know... here in
school we say, one and one, the sum-of-which is two."