Fast account. 30 simple techniques of an oral account. Perelman Ya.

Currently, there are no manuals containing instructions for the rapid implementation of counting operations in the mind. Therefore, we considered it useful to collect in a brief brochure the simplest and most easily absorbed techniques of quick oral account. They are designed for average abilities and do not mean public performances on the stage, but the needs of everyday life. The book that uses the book should remember that the successful mastery of its instructions implies not a mechanical, but a completely conscious disposal of techniques and, in addition, more or less prolonged training. But, having learned recommended techniques, you can perform quick calculations in the mind with the accuracy of written calculations.