###Challenge 1
For challenge 1, I started by putting a container around div 2 and 3. I changed the position of all divs to inline-block. I gave the container a width and a height to allow room for div 2 and three to sit inside. Finally, I floated the container right.
###Challenge 2
For challenge 2, I started by setting margin to auto on div 2. Then, I set div 3's position to absolute and gave it a right value of 0.