Elementary Number Theory is known for its rich exercise sets, careful and rigorous proofs, examples and applications. A full range of exercises helps students explore key concepts and push their understanding to new heights. Computational exercises and computer projects are available for Maple, Mathematica, Sage Math, and the book's many online resources. The 7th Edition is revised throughout for a presentation that is easier to teach and to learn from, while incorporating advancements and recent discoveries in number theory. Several hundred new exercises enhance the exercise sets even further.