Children sometimes try to show you that they know more than you do:

--because they want you to learn something, from them, somehow, unaware that you always do.
--because they DO know more than you do in certain aspects. You'll even be surprised that they know more things now than you did at their age.
--because they want you to know that they are worth educating further.
--because they want you to feel proud of them.
--because they love you.