Problem Solving Strategies: Crossing the River with Dogs - Teacher's Resource Book and Answer Key

Great book. Period.

When I was in college, I had to take a problem solving class for middle school math education. My prof used this book as our only text. We were never given the key. We worked with 3 partners to solve the problems, a chapter a week. Now, I'm using it in my 4th grade class. I also use it in my work as a math tutor. The students get so much out of it because they learn new strategies for solving other problems. One student works with RC cars and didn't realize that the process of elimination was actually a problem solving strategy, he just thought he was doing what he could to get to the root of the malfunction of his cars.