I guess this course (perhaps in common with others of the series) is a sort of cross between a tourist guide and a serious language course. Summer visitors don't really need to go beyond Chapter 1 (saying hello with confidence) and even long stay folk hardly need the complexities of long division (Chapter 7).
The course is a bit uneven with chunks of pretty well incomprehensible written text (Chapter 5) interspersed with useful vocabulary (body parts in Chapter 9) and shopping (Chapter 8).
A literal translation of the spoken text would have been more than helpful (like essential) as the grammer is as wonderful as the country.
Overall the book gives a good 'feel' for the country even if most of the Ylaanbaatar eating places mentioned are now (thankfully) extinct.
I would start by listening to the poetry in Chapter 10.