According to your answer, it looks like you could use some help Place Value. We recommend starting with Volume 1 of the Learn Math Fast System. The beginning of the book will be easy for you, but you will still learn a bunch of stuff to make all math easier for you.
RESULTS: End of 3rd Grade Level, however, the Learn Math Fast System is for all ages. Volume 1 covers all math facts to build a solid foundation in math. There is no mention of grade level within the books.