When children know more than their educators

Teachers may feel helpless as generations of parents have felt whenever the students show there are more things to know than their elders have any idea of. What can parents do? Which of these might work for professional teachers?

• recognize personal limits of knowledge, pat the kid on the back and say, "you're on your own now"
• read up ahead in the textbook and try to teach (learn by explaining)
• guide towards understanding by asking questions and verifying progress
• approach the chaos as a marketing issue.