Reddit reviews The Structure of Economics: A Mathematical Analysis

I know this is a bit old but maybe it still helps. Simon and Blume is a very good book, I think at a similar level than A. Chiang. Also, Sundaram's book is very good for everything related to optimization. It's much narrower in terms of topics but it's great and pretty cheap for a textbook. Finally, you may be able to find Silverberg's book in your library. It's great for the mathematical approach to microeconomics. It's probably to advanced for an into to micro class but keep it in mind for more advanced classes.