In an age of endless information, judgment is the scarce skill. Test your reasoning against students worldwide, across three rounds of deduction, probability, and clear thinking.
Books, the internet, and AI tools are allowed for research, but you must solve the problems yourself. Later rounds are supervised and tool-free, so learn the material now.
Three friends. One always tells the truth, one always lies, one answers at random. Ask one question to find the truth-teller.
See round detailsFrom an open online qualifier to a live, supervised final exam. Full process →
Open online round. Mixed-format screening across deductive logic, probabilistic reasoning, and critical reading.
Study a real research paper in advance, then sit a supervised 60-minute exam on it plus two further problems.
A single supervised exam of about 30 questions, drawing on everything from earlier rounds under real time pressure.
Over $1,500 in prizes, international and national honours, and a certificate for every participant.
No syllabus to memorize. We test how you think, not what you have been taught.
Deductive reasoning. Starting from facts or rules and working out what necessarily follows.
Probabilistic reasoning. Weighing evidence and base rates, and updating sensibly as new information arrives.
Causal reasoning. Telling real causes from coincidence and spotting confounding variables.
Strategic reasoning. Working out how others will act, and choosing accordingly.
Critical reading. Finding hidden assumptions and gaps, and telling a valid case from one that only seems right.
Modelling & estimation. Breaking a vague problem into the parts that matter and reaching a defensible estimate.
Over $1,500 in prizes, plus international and national honours. Full award structure →
Gold, Silver, and Bronze for each age group among the top performers in the Final Round.
The best performers from each participating country receive special recognition.
Recognition for the most committed ambassadors, teachers, and schools.
Every participant receives an official certificate of participation.
Offer GRC as an extracurricular opportunity for students who enjoy thinking hard. Tools, resources, and recognition included.
Register to view student results and documents, cover Semi-Final registration costs for groups, and supervise exams.
Strengthen collaboration with dedicated tools, reduced fees, and recognition for integrating GRC into academic activities.
Access a growing collection of problem sets, training materials, and classroom-ready resources.
Teachers and schools with strong participation and performance receive special honours.
Coordinate a local group, run activities, and represent GRC while building real leadership experience. Full program details →
Reasoning is the foundation of clear thinking, connecting mathematics, language, science, and everyday decisions. GRC gives students the chance to challenge their reasoning skills beyond the typical curriculum.
All current high school and university students, split into Junior, Youth, and Senior age groups. Everyone receives the same problems; higher groups need more points to qualify.
Everyone submits their own solutions. In the Qualification Round you may work with friends and classmates; the Semi-Final and Final Round must be completed alone.
Prizes and awards are worth a total of $1,500, alongside international and national recognition and certificates for every participant.
Get notified about rounds, deadlines, resources, and the next edition.