What a 42 means
The olympiad is two papers on consecutive mornings, three problems each, four and a half hours a paper. Each problem is marked out of seven, so 42 is the ceiling and there is no tie-break above it: everyone who reaches it shares first place. Tang's official entry records rank 1, a gold medal and full marks on all six.
The scale of the achievement is in the denominator. Of 621 contestants in Bath, six wrote flawless papers. The olympiad's rules cap medals at half the field and hand out gold, silver and bronze in roughly a one to two to three ratio, which puts gold itself within reach of about one contestant in twelve. A perfect paper is a different order of rarity again.
The 2019 field
The six perfect scores that year went to Baiting Xie and Zhizhen Yuan of China, Youngjun Cho of South Korea, Jan Fornal of Poland, and Tang and Daniel Zhu of the United States. It is an unusually wide spread: in most years China takes the larger share of the maximums, and in 2024 only one contestant in the world scored 42.
Two perfect papers from a single six-person national team, as the United States managed in Bath, is the kind of result that decides the unofficial country standings. Each country sends at most six contestants, so a third of the American team gave away nothing at all.
What the problems demand
IMO problems are not exercises with methods attached. Each paper mixes algebra, combinatorics, geometry and number theory, and a contestant has ninety minutes per problem on average to find an argument and write it so that a coordinator in another language can check every step.
Partial credit is awarded, which is why most scoresheets are ragged: a seven here, a two there, a zero on the problem nobody solved. A row of six sevens means no argument had a gap, no case was left unexamined and nothing ran out of time.
What is documented about Tang
The International Mathematical Olympiad's official database is the source for everything on this page: the year, the host city, the size of the field, his country, his per-problem scores, his total, his rank and his medal. It is a primary record, maintained by the competition itself, and it is unusually reliable.
It is also narrow. It does not carry ages, schools, home towns, photographs or later careers. No date of birth for Tang appears in the sources used here, which is why this page gives no birth year, and no press coverage naming him was collected for this file.
Where perfect scorers tend to go
The olympiad's own results archive is the only follow-up this page can offer, and it records no further IMO appearance for Tang after 2019. Contestants age out: the competition is for students in secondary education, so a strong year is often a last year.
What happens afterwards is not in the database, and this page will not guess at it. Anyone claiming to know which university he attended, or what he does now, should be asked for a citation, because the official record stops at the scoresheet.
| Person | Country | Milestone | Age / Stat |
|---|---|---|---|
| Colin Shanmo Tang | United States | A perfect 42/42 at the International Mathematical Olympiad, 2019 | — |
| Daniel Zhu | United States | A perfect 42/42 at the International Mathematical Olympiad, 2019 | — |
| Youngjun Cho | South Korea | A perfect 42/42 at the International Mathematical Olympiad, 2019 | — |
| Galiia Sharafetdinova | Russia | A perfect 42/42 at the International Mathematical Olympiad, 2022 | — |
| Ihor Pylaiev | Ukraine | A perfect 42/42 at the International Mathematical Olympiad, 2022 | — |
What is documented — and what is not
✓ Documented
- Scored 42/42 at IMO 2019 in Bath, ranked joint first with a gold medal
- Competed for the United States
- Seven points on each of the six problems
- One of six perfect papers among 621 contestants
? Unverified, disputed or wrong
- No age, date of birth or school in these sources
- No later IMO appearance recorded
- Nothing documented about his studies or career
Questions people ask about Colin Shanmo Tang
What did Colin Shanmo Tang achieve?
A perfect score of 42 out of 42 at the 2019 International Mathematical Olympiad in Bath, sharing first place and taking gold.
How old is Colin Shanmo Tang?
No age or date of birth appears in the sources used here. The IMO's official database does not publish them.
How rare is a perfect IMO score?
Six of the 621 contestants in Bath in 2019 scored 42. In 2024, only one contestant in the world did.
Who else scored 42 in 2019?
Baiting Xie and Zhizhen Yuan of China, Youngjun Cho of South Korea, Jan Fornal of Poland and Daniel Zhu of the United States.
What is the maximum IMO score?
42: six problems marked out of seven each, across two four-and-a-half-hour papers.
Is Colin Shanmo Tang on Wikipedia?
No standalone article is recorded for him in this file. His results are held in the IMO's official database.
Where is Colin Shanmo Tang now?
The sources used here do not say. The official record ends with his 2019 results.
Did he compete at the IMO again?
No later appearance is recorded for him in the results consulted for this page.
Quick quiz: how well do you know Tang’s story?
What was Colin Shanmo Tang's score at IMO 2019?
Where was the 2019 IMO held?
How many contestants scored a perfect paper in 2019?
Sources
- IMO 2019 individual results — International Mathematical Olympiad (official), 2019
- Colin Shanmo Tang - IMO contestant results — International Mathematical Olympiad (official), 2019
Checked by the Geniuses.club editorial team. Ages are given as of September 2026.
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