Section 2.1

1)

“Notice that the additive part of any ring forms an abelian group.” The example at the end of page 8 about zero divisors was a bit confusing. I thought I understood what it means to have a zero divisor but that example confused me. I didn't understand the beginning of page 9 when it states that y – x exists in D+. I didn't understand the proof for the lemma 2.1.3.

2)

One of the things I really liked about studying rings and groups was how they applied to the real world. For example how they were applied to Rubik’s cubes and Sudoku puzzles. I also liked the review on proof by induction.