Come to USA and buy books through amazon.com. Would be much cheaper for you. Also, books written by Nepalese/Indian authors are not very useful in USA. The whole technique of teaching is different in USA. You could review some concepts in calculus while you are in Nepal by borrowing it from your friends. I believe you have some friends who were in engineering field in Nepal. Ask them if you can borrow some calculus books and review some concepts. But, don't buy and bring it to USA. You will have to eventually garbage those books.