How high would the debt stack if it were represented with $1 bills? What if it were represented with the largest denomination in circulation today? How much area would the debt cover if it were represented with a single layer of $1 bills? Could you carpet the United States with its own debt? How much would the debt weigh if it were represented with $1 bills? What if it were represented with quarters?

Answer 1

each bill is 2.61" x 6.14" and is 0.0043" thick
Now you should be able to figure how high the stack would be.
Look up the area of the US and compare the area of the bills.

I'll let you do the google for the size and weight of the bills and quarters.