The teacher was discussing different jobs held by the parents of the students.
When she called on Little Johnnie, she asked, "And what does your father do?"
"Oh, he's a magician," replied Johnnie.
"Really? And what's his best trick?"
"His best trick is sawing people in half."
"Wonderful!" exclaimed the teacher. "Tell me Johnnie, are there any more children in your family?"
"Yes ma'am, I have a half brother and two half sisters."