This book helps students develop their probabilistic thinking by introducing them to the notion of sample space and the use of tree diagrams and geometric regions to represent sample spaces. Many activities present probability in the context of the fairness of games, a topic of great interest to middle-grades students. Notions of population samples, prediction over the long term and the law of large numbers are reinforced through games and engaging problems. The supplemental CD-ROM features interactive electronic activities, master copies of activity pages for students and additional readings for teachers.