This book is awful. I have never seen a book with so many typos and slang in the first two pages. I didn't bother to read any further. I wouldn't be surprised if this book was once an e-book written up from the notes of someone taking the exam themselves and has never been looked at by an editor. The book will be returned as soon as possible. There is one 5 star review on the amazon.co.uk pages amongst the many 1 star reviews, which I assume this is written by the author. Stay well clear.