I= {1, 2}
list all possible subsets of the given set.

There are four subsets of this set:

1) The null set.

2) Itself ({1,2})

3) {1)

4) {2}

     An interesting thing about set theory (which studies the above}.  I thought for years

that set theory was abstract.  Then, a friend of mine studied set theory as a

master's degree thesis in applied mathematics at a local university! 

answer: there are 453.592 grams in a pound.