Time management is an essential skill required to clear entrance exams. To help you with that here is a video which teaches you to perform multiplication of any number quickly using Vedic Mathematics.
To learn Vedic Maths in detail, we recommend the book "How To Become A Human Calculator?: With The Magic Of Vedic Maths" by Aditi Singhal
Vedic Mathematics is a technique for performing mathematical calculation based on a set of 16 Sutras, and their corollaries. It is said to be an ancient system of calculation which was "rediscovered" from the Vedas by Sri Bharati Krushna Tirthaji Maharaj between 1911 and 1918.
Learning Vedic Mathematics gives you an edge while preparing for competitive examinations and from tomorrow we would be sharing many more tricks to help you in calculating quicker and with less errors.