Approach #1: Don’t announce it ahead of time. This is kind of like a pop quiz. One day announce that today is “Amnesty Day”. Students are given class time to work on missing assignments. Work turned in on that day will not be given the 10% penalty. Here’s the best part! Students who don’t have any missing assignments are given free choice as their reward. They can work on computers, read a book, centers, etc.
Approach #2: Announce ahead of time that ___ day is going to be Amnesty Day so students can work on missing assignments at home. All missing assignments turned in on Amnesty Day won’t receive the 10% penalty. Students who have cleared all of their missing assignments will get to participate in free choice. I’m sure you will have some motivated little workers with this approach!