The US Ersatz Math Olympiad is a proof-based competition open to all middle and high school students. Like many competitions, its goals are to develop interest and ability in mathematics (rather than measure it). However, it is one of few proof-based contests open to all middle and high school students.

The USEMO is hosted on the Art of Problem-Solving website. This contest is not sponsored by the Math Association of America (which runs the USAMO).

The difficulty of the contest is intended to be similar to IMO. As part of the learning experience, we aim to provide feedback (rather than just score) to participants. You can read the full USEMO mission statement to get a better sense for the goals of the competition.

The USEMO is largely run on an honor system, although we may offer prizes. Please check the full rules and procedures.

USEMO 2025#

• You can download the problems file for USEMO 2024 now.
• Registration opens around October 1 on AoPS portal. It remains open until end-of-day October 24 or when capacity is reached.
• Day I is Saturday 25 October 2025, from 12:30pm ET to 5:00pm ET.
• Day II is Sunday 26 October 2025, from 12:30pm ET to 5:00pm ET.
• On each day, the AoPS portal will be functional between 12:00 noon ET and 6:00pm ET, to allow some time for setup and for scanning and submitting solutions. The problems are available for download starting 12:30pm ET.
  • You can check your registration status at this link.
• Discussion of problems opens at 7:00pm ET each evening after the exam.
• Volunteers for grading are open at link below.
• Problem proposals were due May 10, 2025.

The organizers of the USEMO are grateful to be sponsored in 2025 by the CoRe Lab, Institute of Artificial Intelligence, Peking University.

Links and downloads#

• Registration and submission portal
• Answer sheet template
• Full rules and procedures
• Mission statement
• Problem proposal guidelines (for authors)

Contact#

The director of the USEMO is Evan Chen. You may use the email $\text{usemo}\texttt{@}\text{evanchen}{.}\text{cc}$.

Archive#

• USEMO 2019 (problems) (solutions and results)
• USEMO 2020 (problems) (solutions and results)
• USEMO 2021 (problems) (solutions and results)
• USEMO 2022 (problems) (solutions and results)
• USEMO 2023 (problems) (solutions and results)
• USEMO 2024 (problems) (solutions and results)

Hall of Fame#

This is a listing of the Top 3 scorers on each USEMO. Further results can be found at the links above. The list below is sorted alphabetically by first name (not by place).

• USEMO 2019: Jaedon Whyte, Jeffrey Kwan, Luke Robitaille
• USEMO 2020: Ankit Bisain, Gopal Goel, Noah Walsh
• USEMO 2021: Eric Shen, Kristie Sue, Ram Goel (with Raymond Feng tying third place)
• USEMO 2022: JunWen Huang, Krishna Pothapragada, Maximus Lu
• USEMO 2023: Hannah Fox, Henrick Rabinovitz, Linus Tang
• USEMO 2024: Alexander Wang, Feodor Yevtushenko, Oron Wang

Volunteer#

• Grading: this is by far the main bottleneck. If you have any capability to read through some submissions, please help! While you need experience reading mathematical proofs to fulfill this role, you do NOT need past competition experience. We will provide marking schemes, and pair up experienced graders with newer ones. You can read more info about the grading here; see also the advice for problem captains.
  You can sign up for grading 2025 here. Grading will start in November 2025 this year. The deadline for grading signup is October 25, 2025.

• Problem proposals: we welcome proposals from anyone, although preference is given to proposals from those who have completed high school. See the problem proposal guidelines. For USEMO 2025, the deadline for submissions is 10 May 2025.

Please contact the directors for further details on these, or if you have other ideas on how you could help out.