Assign Optional Challenge Work
One of the awesome things about digital is how easy it is to provide optional challenges to students. I will post to Google Classroom with the topic of "Optional" or "Challenge." Obviously, I do not expect all students to do it.
For students who did not complete the challenge, you can return the work to them. Even though they did not turn it in. By default, Google Classroom sorts by status. It is easy to view which students chose not to take the challenge. Check the checkbox for the status "Not done." Click the Return button at the top.
Returning uncompleted work removes it from the student's "Not done" list. It allows you to acknowledge that they are exempt, excused, or not required to the assignment.
Leave a Note
From the browser version of Google Classroom, you can leave a mass note to the students who are not done. Let students know it was okay they did not do the optional challenge and that you are removing the activity from their Not done list.
It is likely that after receiving the notification that they did not do the optional challenge they may want to do it now. Work that has been returned has the option to be resubmitted.
Students Click Blue Resubmit Button
Done Counts of Zero
I try hard to keep my Done counts as zero. When the Done count is no longer zero, this alerts me that a student has submitted work since I last looked at it.