Solution to Problem 1: "Four Easy Pieces"

The sum of all sixteen entries is 68, so we need to find four pieces with a sum of 17 each.  As it turns out, there is only one way of finding three squares adjacent to the 9 that have a sum of 8: the 7 and 0 to the left, and the 1 above the 7.  With this piece identified, there is only one way of building the other three pieces such that each piece contains four squares.

Comments: This was the most-solved puzzle in the test, and I thought that it was the second-easiest (behind the comic strip puzzle).  It was a nice introduction, since not much of what was left was this welcoming.