I use these cards as a way to monitor students calling out. I have attached these cards to each student's desk. I advise them that they will not be penalized but a way they can monitor their own behavior. The first day I started this, I was surprised on the HUGE decrease in calling out and the fact that there was no penalty was amazing. I had 2 students who went from calling out at least 25-30 times throughout the day to 3-4 on day 1!!! What a difference!! I would just come around and take my Vis-a-Vis marker and make a little tally without stopping my teaching. I wouldn't say a word to any student, just continued to teach. Try it and let me know how it works for you.