2nd Edition . , correct. and dop. - M. : TEIS, 1994. — 61 s. The book contains various tasks used for a number of years in the classes of mathematical circles, as well as the problems of mathematical Olympiads for schoolchildren of 6-7 classes of 1990-1994. The collection also presents the most interesting activities of the circles . Tasks are accompanied by instructions and decisions. The collection is intended for schoolchildren of grades 5-8, who take the first steps into the fascinating world of mathematics. It will be of greatest benefit to those who solve it entirely, perhaps with the exception of some of the most difficult tasks (this is real). The collection can be useful to teachers of mathematics, heads of mathematical circles and all lovers of mathematics .