Teach with confidence, using the world's favorite English course. Interchange is a four-level, American English course that has been used by over 50 million students worldwide. This Intro Full Contact has 16 units and includes the Student's Book, Workbook, video activity sheets. Inside each book is a single-use code for the Digital Pack to access the Digital Workbook with hundreds of self-graded exercises, audio, videos, and an eBook, all available on the Cambridge One platform. The Digital Pack is mobile-friendly and can be used on a smartphone, tablet, or computer.