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US Ersatz Math Olympiad

The US Ersatz Math Olympiad is a proof-based competition open to all US 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 US middle and high school students.

The USEMO is hosted on the Art of Problem Solving website. This contest is not sponsored by the Mathematical 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.

We hope the next USEMO can run in Fall 2020.

Current instance

Grading is currently underway. Scores will be displayed on the portal on the Art of Problem Solving host website once the grading is done.

Here is a list of ID numbers that submitted for each problem.

Schedule (formerly)

  • Day 1 of exam: Saturday May 23 2020, from 12:30pm ET to 5:00pm ET.
  • Day 2 of exam: Sunday May 24 2020, from 12:30pm ET to 5:00pm ET.

Additionally, an optional test review will be held on 7pm ET each day right after the exam. It will be hosted at The USEMO organizers will present solutions to all three problems on that day and take any questions or comments from the live chat.

Links and downloads

Past USEMO problems, solutions, and results


The directors of the USEMO are Evan Chen, Brice Huang, and Carl Schildkraut. You can reach all three at the email $\texttt{usemo@evanchen}\cdot\texttt{cc}$.


Volunteering is open to anyone who is not themselves eligible to compete. The two biggest things we can use help with are:

  • Grading: this is by far the biggest bottleneck. If you have any capability to read through some submissions, please get in touch with the organizers! 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. If you're interested in this, please contact the USEMO directors at $\texttt{usemo@evanchen}\cdot\texttt{cc}$.

  • Problem proposals: we welcome proposals for problems from anyone who is not eligible for the contest (although the deadline for the 1st USEMO has passed already). See the problem proposal guidelines.

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

Last modified: Wed May 27 18:07:47 2020.