exercise CONCLUSIONS lack researcher mathemtic solution student wa learning medan research careles factor doing mathematic create specify headmaster mastery encoding every operation clas SUGGESTIONS respond skill kind each role demonstrator method external material still command teacher cause sample very problem prerequisite into good master teaching often next similar make proces transformation given analysi improve know must internal concept principle another algebra concluded level divided give CHAPTER mediator error best especially controller held school made solving stimulate junior achievement suggestion not VIII repair before instruction high analyze