A math professor’s six-year-old son knocks at the door of his father’s study.
“Daddy,” he says, “I need help with a math problem I couldn’t do at school.”
“Sure,” the father says and smiles. “Just tell me what’s bothering you.”
“Well, it’s really hard problem. There are four ducks swimming in a pond, when two
more ducks come and join them. How many ducks are now swimming in the pond?”
The professor stares at his son in disbelief.
“You couldn’t do that?! All you need to know is that 4+2 = 6 !”
“Do you think I’m stupid?! Of course I know that 4+2 = 6.
But what does this have to do with ducks!?”