This book is one of the books in 20 Minutes Every Day for Pupil Series. The book series is written on the basis of school hours and simultaneously supporting the textbook. Review is set for key units. Problem types in the book are classic, refined, not dull, not boring, and in various forms, so that students at the primary school are able to master the method of calculation step by step. In addition, very detailed answers are presented in the book. Knowledge focus and difficulty in each lesson are highlighted, the most basic and important exercises are synchronized with the textbook and school hours to provide a 20-minute exercise platform for pupils to improve their math ability in an easier way. In its style arrangement, the book is creative, highly appropriate and personalized. With the new curriculum textbook, each lesson is summarized and analyzed. 20-minute learning help pupils to have much gains and make more progress in a happy learning atmosphere..