The participants in HSSI are high school students between 8th and 12th grade, aged 15 to 18, mainly from specialized Science and Mathematics Secondary Schools in Bulgaria.
   Every participant in HSSI works individually or in a team (less than 3 students), on a freely chosen topic in Mathematics, Informatics and/or Information Technologies under the guidance of a teacher or another specialist. The project (paper and a CD with the application or program for IT) is sent in advance to HSSI. All papers are refereed by specialists and the reports are given to the authors. Papers involving creativity elements are highlighted. The best projects are accepted for presentation in the competitive sessions of HSSI. At these competitive sessions, the authors present their work in front of some audience and the best are rewarded with excellent diplomas.