Knowledge

A mother is driving a little girl to her friend's house for a play date. "Mummy," the little girl asks, "how old are you?"
"Honey, you are not supposed to ask a lady her age," the mother replied. "It's not polite."
"OK", the little girl says, "How much do you weigh?"
"Now really," the mother says, "those are personal questions and are really none of your business."
Undaunted, the little girl asks, "Why did you and Daddy get a divorce?"
"That is enough questions, young lady, honestly!"
The exasperated mother walks away as the two friends begin to play.
"My Mum won't tell me anything about her," the little girl says to her friend.
"Well," says the friend, "all you need to do is look at her drivers license. It is like a report card, it has everything on it."
Later that night the little girl says to her mother, "I know how old you are, you are 32."
The mother is surprised and asks, "How did you find that out?
"I also know that you weigh 140 pounds."
The mother is past surprised and shocked now. "How in heaven's name did you find that out?"
"And," the little girl says triumphantly," I know why you and daddy got a divorce."
"Oh really?" the mother asks. "Why?"
"Because you got an F in sex."