Fall 2018

In the Fall semester 2018, I will be teaching  MATH-UA.0248-001 Theory of Numbers.


MW 3:30-4:45pm in CIWW 201. Recitation F 3:30-4:45 in CIWW 101.

Contact information:

Office 604
bilu @ cims.nyu.edu (remove blank spaces around @)

Office hours:

MT 10:30-11:30am, or by appointment.

Contents of the course:

Topics include: divisibility theory, Euclidean algorithm, congruences, prime numbers, Fermat's theorem, Pythagorean triples, applications to cryptography, classical number-theoretic functions, perfect numbers, quadratic reciprocity.


 12/10 version. Remarks or questions welcome! Pay attention to the fact that these notes do not contain some of the proofs. If you've missed a lecture, make sure to catch up the proofs by borrowing someone's notes


Homeworks are always due in the beginning of Monday's class. If you cannot attend class, you can e-mail me your homework before the beginning of class, or leave it in my mailbox (number 38 on the right side of the mailboxes behind the guard's desk in the lobby of WWH). Late homeworks are usually not accepted, except if you have a valid excuse, which you should e-mail me about in advance. The two lowest homework grades will be dropped.

Homework 1 Solution
Homework 2 Solution
Homework 3 Solution
Homework 4 Solution
Homework 5 Solution
Homework 6 Solution
Homework 7 Solution
Homework 8 Solution
Homework 9 Solution
Homework 10 Solution
Homework 11 Solution

The solutions to the homeworks were mostly written up by Antonios-Alexandros Robotis.


Your TA is Antonios-Alexandros Robotis. Here are some problems you will work on during recitation.


There will be short quizzes during recitation on the following dates:
September 28th
October 12th
November 30th


There will be one Midterm exam, on Monday October 29th. Here are some extra practice problems for the Midterm, with some solutions. 

Midterm  Solutions

The Final exam will be on Wednesday, December 19th, 4-5:50pm. Here are some extra practice problems.


Recommended books

David Burton, Elementary Number Theory, available online here or here
Joseph. H. Silverman, A Friendly Introduction to Number Theory. Chapters 1-6 are available online here

Some advice

Previous years

For my teaching at Courant during the academic year 2017-2018, see here.
For my 2016 and 2017 Algebraic Topology problem sessions at the ENS, see here.