Fermi Problem Update

My ten year old has been doing Fermi problems since I posted here and he continues to request more.  A few problems done so far include:

1. How much paper would you need to make a stack that would touch the den ceiling?
2. How many hairs are there on one of your arms?
3. How much unpopped popcorn would you need to fill your sister’s closet with popped corn? 
4. How much does it cost your parents to feed you for a year?
5. Ignoring Oceans and such, how long would it take you to walk entirely around the world?
6. How many sheets of paper would you need to cover the largest wall in your room?
7. How many revolutions will a car tire make on a drive to Grandma's house?
8. How many pairs of shoes are there in Dallas?

We've also been using problems in the book Guesstimation.