People always want to control time! Learn about how we invent ways to try, from Roman and Mayan calendars to clocks to time zones. Cambridge Discovery Education Interactive Readers are the next generation of graded readers - captivating topics, high-impact video, and interactive exercises designed to motivate and engage. These 96 leveled (A1-B2+), highly engaging titles feature Discovery Education™ videos that are fully integrated into the pedagogy of the readers. Choose from four formats: book plus access code for online content; online only; iOS app; and Android app. The online version of these readers comes complete with a learning management system - class creation, progress tracking, gradebook, and more - which frees teachers from the mundane task of homework correction, and gives students interactive practice anytime, anywhere.