kenгуру простите  конкурс с мировым именем, Mathematical Kangaroo (also International Mathematical Kangaroo and Kangourou sans frontières, the original French name) is an international mathematical competition with more than 40 countries that take an active part in it. There are twelve levels of participation: from grade 1 to grade 12. The competition is held annually on the third Thursday of March. According to the organizers, the key competence tested by the Kangaroo is logical combination, not just pure knowledge of formulas. Because of the rising popularity of the Mathematical Kangaroo in many participating countries, it is currently the most participated scholar math competition: over 5,000,000 students from 47 countries.т. Может в России и платно, но вот не в россии я не платила ни разу.  Впрочем я  еще не за одну олимпиаду не платила, как например за вполне коммерческую ТАКТИК.