Made mental math course

This book describes methods to mental arithmetic as well as professor of mathematics Arthur Benjamin, one of the best current mathematical geniuses, even be applied. There are also shown Memnotechniken to remember numbers. According to Benjamin, people can usually remember only 7-8 figures, but what should be be increased by means of these techniques up to 20 numbers. There are anecdotes about famous computers as Gauss, Fuller, Galois, Bidder, Aitken etc. interspersed.
Some of the methods of calculation are very simple and these methods one remembers even to have applied before. This book is more intended for non-mathematicians to whom I am also counting on yourself. From my perspective, this is the book for each recommended interested arithmetic and mathematics.