These are great for posting "missing" work. In my classroom, subjects are color-coded (Red = Reading, Green = Science, etc.) So, if a student sees his/her green number posted, s/he knows that a Science assignment is missing. Middle School or High School teachers could use different colors for different periods.
This is a file of FINGERPRINT student numbers. They go with my Detective theme. :-) Instead of a subject "color", I used these for field trip slips, etc.
I created these .jpg files to be printed as 4" x 6" photos. Each "photo"/card has 6 student numbers (#1 - 6, #7 - 12, etc.). There are 6 files per .zip to create student numbers 1 - 36. I print mine at Costco ($0.13 each for a total of less than a dollar per set), but you can print them at home, too.
I laminated the cards and cut/separated the individual numbers. I then bought a roll of magnet strips at Michael's, cut 1" pieces and used the strip's self-adhesive to put them on the back of the student numbers to create magnets.
You can put them on any magnetized surface. I started putting them on my white board, but soon found out that it worked better if I put them on cookie sheets so as not to take up precious white board space. I secured cookie sheets to space on my wall where little else fit. :-)
I have uploaded 7 different sets: Blue, Green, Red, Purple, Yellow, as well as "Fingerprints" and "Special Agents" which work well with my classroom Detective theme.