7.5 (first half), due March 16

Congruence classes of groups is really difficult for me to wrap my mind around, I know that with some practice it'll make sense, but I'm not there yet. I think just seeing/working with some different examples would clear this up for me. It's also somewhat confusing to have right cosets (and so do we have left cosets?). It is nice that we have a lot of the same terms/vocabulary just applied in new ways but that they generally work the same with some minor adjustments.