Prerequisites for "A Classical Introduction to Modern Number Theory" by Rosen and Ireland

Question

I want to learn number theory for my programming as many of the questions are related to the mathematics which is being asked in Hiring Challenges as well as for increasing my knowledge of cryptography. I have studied cryptography from Khan Academy and no doubt they were enough for me to pass my exams but I feel that I have just touched the surface of number theory and I was amazed by it. Many of the aptitude exams in India uses the application of number theory. But they only tell you the trick but I want to learn how do this trick work correctly. So I bought the book A Classical Introduction To Modern Number Theory but I am finding some difficulty to understand it. Have I missed something before it which should be read? I know calculus and Discrete Mathematics(not thoroughly)

Answer 1

This book assumes some knowledge of abstract algebra. If you don't know what a group or ring is, then you'll find the book heavy sledding. You might try Ken Rosen's Elementary Number Theory (different Rosen) or Burton's Elementary Number Theory first. I would consider Ireland and Rosen as a good second course in Number Theory.