SON OF BITCH IS!

A little boy was doing Maths homework, saying 2+5 the son of bitch is 7.
3+6 the son of bitch is 9.
His Mother heared this and gasped: "What are you doing?"
The little boy answered:
"I'm doing my Maths homework."
Mother: "And this is how your teacher taught you to do?"
"Yes", he replied.
Then mother asked the teacher next day: "Are you teaching Maths to children by saying 2+2, the son of bitch is 4"
The Teacher started laughing and answered: "What I taught them was '2+2 THE SUM OF WHICH IS 4'."