Clear rules for a fair competition.

Anyone who has not completed secondary school may compete in the official division, regardless of country or grade.

Dual-enrolled secondary students remain eligible. Students in grade 10 and below, or equivalent, are included in the junior ranking. Undergraduates and adults may participate unofficially but do not receive official rankings or awards.

The competition is individual and consists of 20 short-answer problems. Participants have 90 minutes. Every answer is a non-negative integer below 1,000,000,000.

The official competition language is English.

The contest window begins Saturday, November 14, 2026 at 00:00 UTC and ends Sunday, November 15, 2026 at 23:59 UTC.

A participant may start at any time inside that window. The 90-minute timer begins only when the participant starts the contest and cannot be paused.

Participants may use blank or lined paper and writing instruments.

Calculators, computer algebra systems, code, online searching, published references, communication with another person, and outside assistance are not allowed during an official attempt.

Each correct answer is worth one point. There is no penalty for a wrong or blank answer.

Ties are broken by the hardest problem solved, comparing Problem 20 downward. If participants remain tied after all problems are compared, they share the same rank.

Official participants must work alone and must not share, request, or discuss problem content during the contest window.

The organizers may review attempt records and request additional verification when needed to protect the integrity of the results.

If the text of a problem appears publicly during the contest window, that problem is removed from scoring for every participant.

The committee's decision on whether a public disclosure constitutes a leak is final.

The top 30 participants overall and the top 15 junior participants will be asked to submit handwritten solution sketches for three committee-selected problems.

Submissions are due within 72 hours of the request. Failure to provide satisfactory verification may make a participant ineligible for an award.

Gold, Silver, and Bronze designations are based on competition performance. A separate junior ranking is maintained for grade 10 and below, or equivalent.

A Country Top Scorer may be named for countries with at least five official participants. All participants receive digital certificates.

Physical medals are not guaranteed. Any physical gold medals depend on confirmed sponsor support.

Participants may submit a scoring appeal within 72 hours after preliminary results are published.

Appeals must identify the specific scoring issue and include any information requested by the committee. Editorial judgments about problem difficulty are not grounds for appeal.

A participant may be disqualified for receiving or providing outside help, using prohibited tools, sharing contest content, falsifying eligibility information, impersonation, or failing award verification.

The committee may withhold a result while a potential violation is reviewed.

Registration may collect a participant's name, email, school, country, and grade. Participants under 13 register through a parent or teacher.

Publication of a participant's full name or photo is opt-in. Rankings may use the display preferences selected during registration. See the Privacy page for details.