**Instructor:**Gexin Yu, Jones 127, phone: 221-2040, gyu@wm.edu**Meeting time and location:**TR 12:30-1:50pm Jones Hall 113

**Web pages:**- Math 412 Section 01 (Blackboard link (to grade center))
- http://gyu.people.wm.edu/Fall2017/Math412/Math412.html

**Office Hours:**TR 11-12 or by appointment. Homework help session every Wednesday 2-3pm at Jones 131.**Text:**Elementary Number Theory, 6th Edition. Author: Kenneth H. Rosen. ISBN: 9780321500311. Publisher: Pearson. An earlier version of the book is also fine.**Course goal:**This is an introduction course on number theory and some related algebra, with an emphasis on solving equations in integers. Some main topics will include division theorem and Euclidean algorithm, unique prime factorization, congruence arithmetic, linear Diophantine equations, Pell equation, Gaussian integers and quadratic integers, quadratic reciprocity. If time permits, we may cover a little of ideals and prime ideals.**Tests:**there is no mid-term tests.**Final Exam:**a comprehensive final exam will be offered on**Wednesday Dec 20 from 9am to 12pm**. Location TBD (usually the lecture room).**Homework:**There will be weekly homework assignments. We cannot emphasize the importance of homework enough. Although understanding material while you read the text or listen to lecture is certainly important, your most important studying will be in completing the homework assignments.Start homework early and work steadily!

**Help Session:**A weekly homework help session will be offer every Wednesday 2-3pm at Jones Hall 131.**Attendance:**Regular attendance is critical for your success in this course. I expect your presence at every lecture.**Grading:**Your final grade is calculated as follows:- Homework 60%
- Final Exam: 40%

The letter grade is assigned using the scale:

A > 93 > A- > 90 > B+ > 87 > B > 83 > B- > 80> C+ > 77 > C > 73 > C- > 70 > D+ > 67 > D > 63 > D- > 60 > F

**Honor Code:**Students will uphold William and Mary's stated honor code as it is written, any infractions will be referred to the Honor Council.