The fact is that no other science provides the possibility of a deep meaningful transition from visual-effective to figurative, and, then, to opposite rays logical thinking. No other occupation can give an opportunity to know the process of analysis and synthesis through classification, grouping, comparison. It sharpens the child's mind, develops flexibility of thinking, teaches logic. All these qualities will be useful to children and not only when studying at school. Mathematical development is not limited to teaching a preschool child to count, measure and solve arithmetic problems. It is also the development of the ability to see, discover properties, relationships, dependencies in the surrounding world, the ability to “design” them with objects, signs, words.