According to your answers, it looks like you have a solid foundation in math, however, you missed this one problem. Area of an odd shape is taught in Volume 4 of the Learn Math Fast System. If these last few problems were difficult for you, then you should start with volume 4 of the Learn Math Fast System.
RESULTS: The End of the 8th Grade Level, however, the Learn Math Fast System is for all ages. Volume 4 covers 3rd - 8th grade geometry and the metric system, but there is no mention of grade level within the books.