An easy-to-use reference book contains in a compressed form all the material on mathematics for an elementary school course. All rules and definitions are presented in the form of clear logical blocks, tables and diagrams. The application of all rules is shown in the examples. Thanks to this form of feeding, the material is absorbed much better and faster. Topics follow each other in the same order as in popular textbooks. A manual that fully complies with the requirements of the new GEF of primary general education will become an assistant not only for students, but also for parents who will be comfortable at any time to control the assimilation of the school curriculum by the child.