By 16th May 2021, there are 1061 registered participants from 71 countries (the list of countries is given below). During the first seven weeks, 23 solutions were submitted, out of which eight were correct.
The final deadline for Problem 5 is 13:00 GMT, 20th June.
Correct solutions were submitted by:
| First Name | Surname | Country | School/University | date | time |
| Nikita | Semenin | Russia | Moscow Institute of Physics and Technology | 26/04/2021 | 20:39 |
| Zhening | Li | Canada | Sir John A. Macdonald Secondary School | 02/05/2021 | 14:07 |
| Huiyuan | Wang | China | University of Cambridge | 02/05/2021 | 17:07 |
| Kyle | Bomeisl | United States | Rutgers University | 02/06/2021 | 11:07 |
| Vlad-Ștefan | Oros | Romania | “Grigore Moisil” Informatics High School | 03/06/2021 | 09:31 |
| Pieter | Van Steenweghen | Belgium | Imperial College London | 12/06/2021 | 14:29 |
| Ricards | Knipsis | Latvia | University of Manchester | 13/06/2021 | 12:54 |
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.