Section 2.6

Difficult: I had a hard time following the proofs of the two Lemmas given by Gauss. They were long, and I got lost early, which didn't help.

Reflective: I find it interesting that we can easily determine if a number is a quadratic residue, but determining what x is, is computationally hard. I find it so interesting that it can be so easy to prove existence without proving what an item is.