Hello there, I bought Magical Book On Quicker maths, book for my practice of competitive exams, referred by my friend. And found it is very useful.It has shortcut formulae of addition, subtraction, division, multiplication, square, square root, cubes and cube root etc., It is useful for SSC, IBPS, SBI PO like tightest quantitative maths. More practice questions available here.Please buy and study.You also will found useful