NB! The deadline for Problem 3 is extended until 14th April, 23:59GMT.
By 11th April 2021, there are 1019 registered participants from 71 countries (the list of countries is given below). During the first four weeks, 53 solutions were submitted, out of which 17 were correct.
Correct solutions were submitted by:
| First Name | Surname | Country | School/University | date | time |
| Zhening | Li | Canada | Sir John A. Macdonald Secondary School | 28/02/21 | 20:37 |
| Huiyuan | Wang | China | University of Cambridge | 01/03/21 | 08:56 |
| Yuechen | Zhu | China | Peking University | 01/03/21 | 15:22 |
| Lotus | Chen | China | No.2 High School Shijiazhuang | 01/03/21 | 15:39 |
| Nikita | Semenin | Russia | Moscow Institute of Physics and Technology | 01/03/21 | 17:56 |
| Oliwier | Urbański | Poland | Liceum Ogólnokształcące nr 7 w Poznaniu | 02/03/21 | 14:11 |
| Eddie | Chen | United States | West-Windsor Plainsboro High School North | 06/03/21 | 02:05 |
| Qian | Lin | China | University of Oxford | 11/03/21 | 23:47 |
| Yanjun | Zhou | United Kingdom | University of Oxford | 16/03/21 | 06:26 |
| Antonia | Ghita | Romania | International Computer High School of Bucharest | 17/03/21 | 08:43 |
| Jie | Wang | China | Zhangjiakou No.1 Middle School | 24/03/21 | 03:11 |
| Ameya Vikrama | Singh | India | FIITJEE Junior College | 25/03/21 | 08:20 |
| Vuk | Hip | Serbia | Mathematical grammar school | 01/04/21 | 14:35 |
| Pieter | Van Steenweghen | Belgium | Imperial College London | 03/04/21 | 23:02 |
| Dušan | Beguš | Serbia | Mathematical Grammar School | 06/04/21 | 21:36 |
| Sebastián Andrés | Arévalo Aguirre | El Salvador | Instituto Emiliani | 07/04/21 | 22:36 |
| Timothy | Ho | Singapore | Gap Year | 09/04/21 | 14:15 |
Participating countries: Algeria, Azerbaijan, Australia, Bangladesh, Belarus, Belgium, Bosnia and Herzegovina, Bolivia, Brazil, Bulgaria, Cambodia, Canada, China, Croatia, Czechia, Egypt, El Salvador, Estonia, Finland, Georgia, Germany, Greece, Hungary, India, Indonesia, Iran, Israel, Italy, Japan, Kazakhstan, Kenya, Korea, Kyrgyzstan, Latvia, Lebanon, Lithuania, Macedonia, Malaysia, Mexico, Moldova, Mongolia, Nepal, Nigeria, North Macedonia, Pakistan, Peru, Philippines, Poland, Romania, Russia, Saudi Arabia, Serbia, Singapore, Slovakia, Slovenia, South Africa, South Korea, Spain, Sri Lanka, Sweden, Switzerland, Syria, Taiwan, Thailand, Turkey, Turkmenistan, United Arab Emirates, United Kingdom, United States, Uzbekistan, Vietnam.