I'm required to keep my badge on me at all times, and this small hack has been a lifesaver! I make a small table with my students, class numbers, and lunch number. It has saved me from teacher panic mode with drills and emergencies by having my roster with me at all times. I put their lunch numbers, too, because sometimes my kiddos bring their lunch 98% of the time then need hot lunch and don't always have their number.
The editable PDF has 8 tables. Each table has 6 columns and 12 rows. If this table doesn't fit your needs, I have included my table measurements to create your own via Microsoft word or other similar program.