You can use these at the end of class as a form of formative assessment. Students will write 3 things they learned, 2 important details, and 1 question they still have. This will help assess the lesson just taught and check for understanding.
QR Codes in the classroom for a number of activities. QR codes get students used to using technology in a fun and creative way. The student would grab a cube and complete each of the activities as part of a daily task.