The cases cover the backs - where we originally had numerated stickers showing which iPad was which. Now we have gone with an idea originated by iPad colleague Carolyn Skibba at Burley Elementary - change the backgrounds and lock screens of each iPad to its number. In cases where the iPads are truly 1:1 - that is a single student is using a single iPad all day, every day - many teachers choose to take a picture of the student holding a number and use it as the background. However, I teach a differentiated classroom so although during each period there is a 1:1 student to iPad ratio, three sets of students cycle through the devices each day. Therefore, I used generic numbers as the wallpaper. To do this, I typed the numbers in a Pages document on my MacBook and took a screenshot of the number. I then uploaded all of the numbers to my Google Site and was then easily able to download the picture and set it as the wallpaper/lockscreen from each iPad.