This book designed according to the child psychology, modern principles of teaching and latest mathematical trends. The interest and receptive power of the students is kept in consideration. The subject and language is made easy, charming and interesting. The units are divided on the basis of scientific method and learning process. Scientific decimal system used in operations and measurements. Unnecessary long methods of solutions are neglected rather the right methods based on decimal system are given. All the ingredients of I.Q. change of object, change of field, change of time and change of degrees of characters, etc. is included. The fundamental and working principles of Mathematics are explained with examples related to the experience and environment of the children. Many necessary and attractive pictures are given. The subject-matter is classified from simple to complex. All the questions of some exercise are oral (Mental Mathematics). Revision of the previous exercise is also essential with the help of Miscellaneous Exercise.