The 2023 CSU Putnam team.

Left to right: Kandin Theis, Justin Taylor, Joshua Palmer, Ally Claar, Melia Henrichsen, Eve Pidcock, Emma Slack, Jacob McCann (coach), Jae Hwang Lee (coach), Amari Stepanik, Ignacio Rojas (coach), Kendall Foreman

What is the Putnam?

The Putnam is an annual mathematics competition for college students, and a fun way to expose yourself to new challenging math problems. The exam is typically held on the first Saturday of December. In the fall semester, please sign up to take the Putnam exam and make sure to choose Colorado State University as your institution!

The 2024 Putnam exam will likely be held on December 7.

Here is the Putnam Mathematical Competition website, and here is the Wikipedia page.

What is the Putnam seminar?

We will be holding weekly practice sessions, during which we will try to solve interesting problems together. The emphasis will be on learning from each other, so please stop by and share your ideas! It's definitely okay if you can't make some of the practice sessions.

You are welcome to attend the practice sessions even if you can't make the exam, and you are welcome to take the exam even if you can't make the practice sessions.

In Spring 2024 we will be meeting roughly every other Friday at 4:00 PM in Weber 201.

How do I get involved?

Stop by one of the practice sessions! Or, contact Maria Gillespie (maria [dot] gillespie [at] colostate [dot] edu) for information or to get added to our email list.


Spring 2024 Schedule

Date (tentative, subject to change) Topic
February 2 Review of 2023 Putnam exam - part I
February 16 Review of 2023 Putnam exam - part II
March 1 Maria - Combinatorics
March 29 Kandin Theis - Inequalities
April 12 Quang Dao
April 26 Sandra Nair
May ??? - TBD Putnam hike!


The list of tips and tricks that CSU students and coaches are actively putting together as we go through problems in practice. This links to the view-only version of the document.

Here are Putnam problems 1985-present and solutions 1995-present.

Here are Putnam problems and solutions 1994-present.

Here are Putnam problems and solutions 1938-2003.

Here are Putnam problems and solutions 1980-2005.

Here are Putnam problems 1980-2010.

The book Putnam and Beyond by Gelca and Andreescu organizes problems by topic, presents examples, and contains practice problems. It is freely available to CSU students as a pdf.

Past years' schedules and photos

Fall 2023 Schedule

Date (tentative, subject to change) Topic
Sept 1 (Friday) Introduction and Induction
Sept 15 (Friday) Eve - Algebra and Groups
Sept 28 - THURSDAY Chris Liu - Logic and Proofs
Oct 13 (Friday) Quang Dao (guest)
Oct 26 - THURSDAY Jae Hwang Lee
Nov 10 (Friday) Ignacio Rojas
Dec 2 (Saturday) Putnam exam!

Spring 2023 Putnam hike

Spring 2023 Schedule

Date Topic
Feb 10 2022 Putnam review
Feb 24 Speed rounds from easier contests
March 10 J Lee - Problems from 2019 contest
March 24 Ignacio Rojas - Induction
March 31 Maria - Cyclic quadrilaterals
Apr 7 Jacob McCann - TBD
Apr 28 Maria - Putnam geometry problems
May 10 Putnam hike!

Fall 2022 Schedule

Date Topic
Aug 29 Intro, some sample old Putnam problems
Sept 12 Speed rounds from easier contests
Sept 26 Calculus
Oct 3 Algebra - Jacob McCann
Oct 10 (Colloquium - no practice)
Oct 17 Geometry - Jae Hwang Lee
Oct 24 (Colloquium - no practice)
Oct 31 More geometry - Jae Hwang Lee
Nov 14 Combinatorics - Maria Gillespie
Nov 28 Review/prep/photos/swag
Dec 3 Putnam exam!

Fall 2020 Schedule

Date Topic, problems discussed
Aug 31 Putnam 2000 exam, A1 and A2
Sep 14 Putnam 2000 exam, A3 and B2
Sep 28 Putnam 2000 exam, A5 and B4
Oct 12 Proof writing: Putnam 2000 exam, A2, A5, B1, B2
Nov 2 Putnam 2003 exam, A1 (using bijections) and A2 (using AM-GM)
Nov 16 Putnam 2003 exam, A3
Dec 7 Brainteasers and SET

Spring 2020 Schedule

Date Topic, problems discussed
Jan 27 Putnam 2019 exam: B1
Feb 3 Putnam 2019 exam: A1, A2, A4
Feb 10 Andre Leautaud, Section 2.2 on polynomials
Feb 17 Taylor Rogers, Section 1.5 on invariants and semi-invariants
Feb 24 Colloquium
Mar 2 Colloquium
Mar 9 Jack Pfaffinger, Multivariable optimization and Lagrange multipliers
Apr 27 Maria Monks Gillespie, Section 2.1.5 on the Arithmetic Mean - Geometric Mean Inequality.
The meeting will be on zoom.

Fall 2019 Schedule

Date Topic, problems discussed
Sep 9 First meeting: Pigeonhole principle, and Putnam 2010 exam
Sep 23 Putnam 2010 exam, A1 and B1
Sep 30 Putnam 1984 exam, A1 and B1
Oct 7 Generating functions
Oct 14 Generating functions 2014 A1, 2015 A2
Oct 21 Generating functions plus more 2015 A2, 2008 A2
Oct 28 Problems sheet, 2001 A1, 2002 A1
Nov 4 Proof writing / sharing!
Nov 11 Problem sheet, 1988 A1, 1988 B1, 2009 A1
Nov 18 Problem sheet, 2010 A2, 1991 A1, 1993 B2
Dec 5 Dinner at Henry's!
Saturday, Dec 7 Putnam exam!

Spring 2019

In Spring 2019, instead of studying for the Putnam exam, we did a joint research project exploring the conjecture that the Vietoris-Rips simplicial complex of any set of points in the plane, at any scale parameter, is always homotopy equivalent to a wedge sum of spheres!

Fall 2018 Schedule

Date Topic, problems discussed
Aug 27 Pigeonhole principle, and Putnam 2015 exam, B1
Sep 10 Sean Walters: Putnam 2015 exam, and pigeonhole principle
Sep 24 Putnam 1997 exam, B2
Oct 1 Putnam 1997 exam, A4 and A5
Oct 8 Putnam 1994 exam, A2
Oct 15 Putnam 1994 exam, A1, B1, B2, B3
Oct 29 Putnam 1983 exam, B1 and part of A2
Nov 12 Putnam 1983 exam, A1 and A2
Nov 26 Sean Walters: Putnam 1990 and 2006 exams, A1 from 2006
Dec 1 Putnam exam!

Spring 2018 Schedule

Date Topic, problems discussed
Jan 29 Putnam 2017 exam, B2
Feb 5 Putnam 2017 exam, B1 and part of A1
Feb 12 Will van Noordt, Section 3.4 on equations with functions as unknowns, #536
Feb 19 Jingya Li, Combined integral method
Feb 26 Sheldon Deeny, Section 2.2.5 on irreducible polynomials, #182, 183
Mar 5 Sean Walters, Section 2.3.3 on the inverse of a matrix, #229
Mar 26 Henry Adams, Section 6.1.1 on set theory and combinatorics of sets, #823
Apr 2 Ethan Coldren, Section 6.1.3 on combinatorial geometry, #837, 841
Apr 9 No meeting - Henry has a visitor in town
Apr 16 Dinner at Henry's!

Fall 2017 Schedule

Date Topic, problems discussed
Aug 28 Putnam 1999 A1 and pigeonhole principle: "Prove that among any 5 integers there are always three with sum divisible by 3"
Sep 11 Putnam 1999 A3 and pigeonhole principle: "At least 6 Coloradans with the same number of hairs on their head", and "At least two arrows within 1 meter"
Sep 18 Putnam 1999 B1, "Probability two random triangles inscribed on the circle intersect", and "Probability two integers are relatively prime"
Oct 2 Putnam 2011 B1 and "Given three points sampled uniformly at random from a circle centered at the origin, what is the probability that the origin is contained in the resulting triangle?"
Oct 9 Putnam 2011 A4 and "Prove that (n-1)/(n+1)<cos(π/n) for all integers n≥4"
Oct 30 Putnam 1986 B1, Putnam 1988 A1, Putnam 2007 B1
Nov 6 Putnam 1991 B1, Putnam 2009 A1, Putnam 2001 A1
Nov 18 Putnam 1988 B1, Putnam 1991 A1, Putnam 2008 A1, Putnam 2010 A1
Nov 27 Putnam 1992 B1, Putnam 2001 A2, Putnam 1997 A4
Dec 2 Putnam exam!

Spring 2017 Schedule

Date Topic, problems discussed
Jan 23 Putnam 2016 exam, B1 and A4
Jan 30 Nabeel Moin, Section 3.2.1 on Taylor series
Feb 6 Ethan Coldren, Section 2.4 on abstract algebra
Feb 13 Sean Walters, Section 4.1.2 on the coordinate geometry of lines and circles
Feb 27 Will van Noordt, Section 4.1.2 on factorization and divisibility, and Sylvester's theorem
Mar 6 Dinner at Henry's!
Mar 20 Bowen Li, sequences and series, including Section 3.1.4, and 2016 B6, and #360 on page 120
Mar 27 Bowen Li, sequences and series, #353 and #354 on page 119
Apr 3 Ethan Coldren, Section 6.2.2 on generating functions
Apr 17 Section 6.2.2 on generating functions, #867, #870, #872
Apr 17 Putnam 2005 exam, B1

Fall 2016 Schedule

Date Topic, problems discussed
Aug 24 Putnam 2013, A1 and B1
Aug 31 The pigeonhole principle
Sep 7 The pigeonhole principle, part 2
Sep 14 Ethan Coldren, Section 4.1.3 on conics & other planar curves, #604
Sep 21 Section 4.1.3 on conics & other planar curves, #606, #616
Sep 28 Peter Muller, sheet of problems, 2009 A1
Oct 5 Sheet of problems, 2015 A1, 2014 A1, 2012-A1, 2010 B2, 2012 A1
Oct 12 Putnam 1998, A2 and B1, and from prior weeks
Oct 19 Putnam 1995 exam, A1 and B2
Oct 26 Putnam 2007 exam, B1
Nov 2 Nabeel Moin, Section 2.3.1 and 2.3.2 on matrices and determinants, #203, #205, #207
Sunday Nov 6 Practice exam! 2003 side A, and 2000 side A and B1
Nov 16 Discussed practice exam
Nov 16 Peter Muller: Analysis section from Putnam and Beyond
Dec 6 Putnam exam!

Spring 2016 Schedule

Date Topic, problems discussed
Feb 22 Putnam 1996 exam, A1
Feb 29 Gavin Stewart: Section 1.1 on proofs by contradiction, #4, #8
Mar 7 Brooks Adams: Section 1.2 on mathematical induction
Mar 21 Ethan Coldren: Section 6.1.5 on Ramsey theory, #854
Mar 28 #855, #24
Apr 11 #25, both combinatorially and by induction
Apr 18 Putnam 2015 exam, A1, B1, B4, A6
Apr 24 Dinner at Henry's!

Fall 2015 Schedule

Date Topic, problems discussed
Oct 13 Putnam 1984, A1, A2, B1, B2
Oct 20 Putnam 2010, A1, A2, B1
Oct 27 Putnam 2002, A1, A2, A4
Nov 3 Putnam 2008, A1, A2, B1, B2
Nov 10 Putnam 2009, B1, A2, A3, A5
Nov 17 Putnam 2004, A1, A2
Nov 24 Putnam 2001, A1, A2, B3
Dec 5 Putnam exam!
Dec 6 Recap of 2015 exam

The 2022 CSU Putnam team.

Left to right: coaches Jae Hwang Lee and Chris Liu, participants Evelyn Pidcock and Jillian Eddy, and coach Maria Gillespie.

Not pictured: Naeem Moin and Luke Askew.

2021 team (left to right): Jae Hwang Lee, Chris Liu, Evelyn Pidcock, Jillian Eddy, Maria Gillespie. Not shown: Luke Askew and Naeem Moin.

2020 Online team: Luke Askew, Nikita Lavrenov, Derek Moran, Tyson O'Leary, Naeco (Nate) Pasternak, Taylor Rogers, James Rudd (not pictured), Jenna Sikau, Yefei Zhang.

2019 team (left to right): Maria Monks Gillespie, Andre Leautaud, Luke Askew, Taylor Rogers, Sophia Ressler, Jenna Sickau, Henry Adams, Nikita Laurenov. Not pictured: Juanita Duque Rosero, Jingya Li, Naeem Moin, Naser Moin, James Rudd.

2018 team (left to right): Henry Adams, Yuling Wu, Jingya Li, Yujia Chen, William van Noordt, Ethan Coldren, Andre Leautaud, Matt Beirne, Luke Askew, George Laird. Not pictured: Sean Walters.

2017 team (left to right): Zhi Li, Bowen Li, Sheldon Deeny, Nathan Larson, Will van Noordt, Amber Moin, Ethan Coldren. Not pictured: Henry Adams, Sean Walters.

2016 team (left to right): Zhi Li, Henry Adams, Bowen Li, Will van Noordt, Ethan Coldren, Brooks Adams, Joseph Gelfand, Colin Roberts, Doran Wood, Chase Ashby. Not pictured: Sean Walters, Amber Moin, Sid Katz, Peter Muller, Nabeel Moin.

2015 team (left to right): Henry Adams, Ethan Coldren, Gavin Stewart, Nabeel Moin, Amber Moin, Katy Sieviec. Not pictured: Sean Walters.