Keeping student supplies organized is always a problem and they seem to get lost or "stolen" often. In order to help remedy this, have a desk check each afternoon. The students should take a few minutes to organize their books, notebooks, and supplies to see if anything is missing. Students often accuse each other of stealing, but most likely their things are just misplaced due to untidiness. You can then go around the room and make sure everything looks acceptable. This responsibility may eventually be given to the students as a classroom job.