well be careful here, the lines are quite equivocal, perhaps you'll not be able to do what you are thinking; after you finish reading the book. Nevertheless it's more or less a good (if not great) vedic mathematics book. Students with an overall knowledge of elementary mathematics and those willing to speed up mental calculations may find it fascinating and even useful. Then if you are a high school or college student and love maths or think you're good at it, most likely you've come across these tricks and shortcuts