[diegof79]

I love projects like these. Even when I took algebra and calculus in university, it’s good to refresh and go deeper into the concepts many years later.

However, a small critique to the author: the audience of this book is not clear. It says “basic” math, but then in chapter 1, the group's explanation starts with this sentence: “The additive group of integers (Z,+) and the cyclic group Z/Zm.” Maybe it was a draft note. To be fair the paragraphs that follow attempt a more basic explanation of groups, but even my “Algebra I” book at the university was friendlier than that.

[HelloNurse]

That is clearly a "note to self" that remained in the full text. The following paragraph has a regular definition of group.