Fast account: thirty simple oral account techniques

Currently, there are no manuals containing instructions for the quick performance 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 speaking on the stage, but the needs of everyday life. Using the book should remember that the successful mastery of its instructions does not imply a mechanical, but a completely conscious disposal of techniques and, in addition, more or less prolonged training. But, having learned the recommended techniques, you can perform quick calculations in the mind with the accuracy of written calculations