Vedic Mathematics or 'Sixteen Simple Mathematical Formulae from the Vedas' was written by His Holiness Jagadguru Sankaracarya Sri Bharati Krsna Tirthaji Maharaja of Govardhana Matha, Puri. It deals mainly with various Vedic mathematical formulae and their applications for carrying out tedious and cumbersome arithmetical operations, and to a very large extent, executing them mentally. In this field of mental arithmetical operations, the works of the famous mathematicians Trachtenberg and Lester Meyers (High Speed Maths) are elementary compared to that of Jagadguruji.
Some people may find it difficult, at first reading to understand the arithmetical operations although they have been explained very lucidly by Jagadguruji. It is not because the explanations are lacking in any manner but because the methods are totally unconventional. Some people are so deeply rooted in the conventional methods that they, probably subconsciously, reject to see the logic in unconventional methods.