A Problem Posing Approach That Have Cooperative Instructional Background to Increase Mathematics Instructional Effectiveness - Haerul Syam; Study Program of Mathematics Education of Elementary School of Postgraduate Program of State University of Malang. Supervisor: (1) Dr. Cholis Sa’dijah, M.Pd., M.A. (II) Prof. Dr. Ipung Yuwono, M.S., M.Sc. (2009)