RD Sharma is one of the best book authors and the way he have wrote his book for mathematics is a commendable job! The book have for all classes is well detailed . I have studied from RD Sharma till my 12th standard . What I really like about the book is that it have many examples and the examples vary from the easiest to the toughest ones. If you have done this book thoroughly there is no chance you cannot score more than 90% marks in mathematics and it is something coming from my very own experience.