This critical thinking worksheet involves problems related to water conservation, destruction of rain forests, endangered species, and the importance of reducing, reusing and recycling. It is geared for students in grades 4 - 6. It would be perfect for integrating math and science studies about the environment. I enjoy using it with my class as a review on Earth Day. Because some of the problems are more involved, it can be used in one sitting or can be broken up and used in more than one sit