Mathematical Kangaroo (also known as Kangaroo challenge, or jeu-concours Kangourou in French) is an international mathematics competition in over 77 countries. There are six levels of participation, ranging from grade 1 to grade 12. The competition is held annually on the third Thursday of March. The challenge consists of problems in multiple-choice form that are not standard notebook problems and come from a variety of topics. Besides basic computational skills, they require inspiring ideas, perseverance, creativity and imagination, logical thinking, and other problem-solving strategies. Often there are small stories, intriguing problems, and surprising results, which encourage discussions with friends and family. It had over 6 million participants from 57 countries in 2014. In 2022, it has 84 participants countries and claims to be the largest competition for school students in the world. History Mathematicians in Australia came up with the idea to organize a competition that underlines the joy of mathematics and encourages mathematical problem-solving. A multiple-choice competition was created, which has been taking place in Australia since 1978. At the same time, both in France and all over the world, a widely supported movement emerged towards the popularization of mathematics. The idea of a multiple-choice competition then sprouted from two French teachers, André Deledicq and Jean Pierre Boudine, who visited their Australian colleagues Peter O’Holloran and Peter Taylor and witnessed their competition. In 1990, they decided to start a challenge in France under the name Kangourou des Mathématiques in order to pay tribute to their Australian colleagues. The particularity of this challenge was the desire for massive distribution of documentation, offering a gift to each participant (books, small games, fun objects, scientific and cultural trips). The first Kangaroo challenge took place on May 15, 1991. Since it was immediately very successful, shortly afterward they spread the idea in Europe. In May 1993, three teams of teachers from Romania, Poland and Bulgaria participated in Kangaroo together with France. After that, Kangourou des Mathématiques invited mathematicians and organizers of mathematical competitions from several European countries. All of them were impressed by the increasing number of participants in the Kangaroo challenge in France: 120 000 in 1991, 300 000 in 1992, half a million in 1993. In seven countries – Belarus, Hungary, The Netherlands, Poland, Romania, Russia, and Spain – teams of teachers decided to also organize the contest in 1994. It was a great success in all of these countries. An