Teach fact families in a flash with Lightning Lessons: Instant Units! This self-contained, standards-based unit teaches important strategies while introducing fun facts and exciting classroom activities. Your class will study and explore making estimates, relationships among numbers, number systems, and more. Poster activities, inventive classroom exercises, and links to technology will keep students engaged and excited throughout the unit. This Lightning Lesson includes teacher instruction pages, reproducible student pages, vocabulary words, assessment pages and all the materials you need to teach about time.