There was this little girl who came and sat down on a park bench next to a little boy
After a few seconds, the little girl looked over at the boy and she said
"Are you any good at math?"
And he said, "I think so"
And she said, "Well, answer me this...
A shepherd had twenty sick sheep
One died, how many were left?"
And the boy thought, and he said, "25"
And she said, "No, think again
Listen carefully
A shepherd had twenty sick sheep
One died, how many were left?"
And the boy thought and thought and said
"25!"
She said, "No, no, no", she said, "Listen carefully
A shepherd had twenty sick sheep
One died, how many were left?"
And the boy thought and he smiled and he said, "19"
And she said, "That's right, and they all got better"