This PowerPoint presentation gives basic background information about momentum. It also includes five practice problems that you can use with your class to assess their understanding of momentum.
The presentation was designed for upper elementary/lower middle school grades. It covers just the basic principles of momentum, for instance the idea that an object with more mass will have more momentum or that an object with more momentum can knock things over more easily.
This would be a great teaching tool to supplement a textbook reading as well as a good formative assessment for your students!