The Trachtenberg Speed System of Basic Mathematics

ISBN-13: 9780285629165 / Angielski / Miękka / 1989 / 272 str.

Jakow Trachtenberg

Opis

First developed during WW2, the Trachtenberg speed system makes possible high-speed arithmetical calcula tions with a remarkable degree of accuracy. The system has e ven been known to beat computer calculations - in some insta nces - in terms of speed '