Plickers is a powerfully simple tool that lets teachers collect real-time formative assessment data without the need for student devices.  Use Plickers for quick checks for understanding to know whether your students are understanding big concepts and mastering key skills.

 Plickers website:  https://www.plickers.com/
Standard plicker card set:  https://www.plickers.com/cards

 This is an app for the teacher to use:
iOS - https://itunes.apple.com/us/app/plickers/id701184049?mt=8
Google Play - https://play.google.com/store/apps/details?id=com.plickers.client.android