10 great pop duets for easy piano! Play with a friend or with the online audio! Songs: All of Me (John Legend)  Grenade (Bruno Mars)  Happy (Pharrell Williams)  Hello (Adele)  Just Give Me a Reason (P!nk featuring Nate Ruess)  Roar (Katy Perry)  Shake It Off (Taylor Swift)  Stay (Rihanna)  Stay with Me (Sam Smith)  Thinking Out Loud (Ed Sheeran). The audio tracks are accessed online using the unique code in each book and can be downloaded or streamed. The files include PLAYBACK+ tools that allow you to change the tempo without altering the pitch.