Hi Thawdar,
I am not sure what roger covers, so I can't really tell you anything about it.
However, I am letting you know if you get the difficult testlet, you will most likely see some of the hard NINJA questions.
The good part is… a lot of the actual test exam questions is “very very very” similar to NINJA (you know what I mean.. )
I would suggest you post out some of the questions that you don't understand and perhaps someone can get you the explanation.
Personally, I think most of the math was okay. These are the same questions I got when I study cost accounting in college. All my teachers used CPA exam questions on the mid-terms and finals.
I used “Introduction to managerial Accounting” 5th edition by Peter Brewer, Ray Garrison and Eric Noreen. It covers all the cost accounting material. All I did is revisit the book and flip through all the equations. (No need to read the material).
Posting questions will be your best option.
(Will be back Thursday evening. Got to work..going to bed now)
New York - NYC
Passed CPA Exam (11/2014)
In search for a position in NYC that will fulfills the license requirement.