This interactive SMARTboard activity is a set of flash cards that have many uses. One of the numbers is missing in an addition or subtraction problem. All slides are self checking and answers are revealed with a quick click of the button. Problems are basic math facts up to 20. Great to use in a teacher directed lesson, small group, or independent center for repetition and reinforcement. Also a great tool to use to work on speed and memory of basic facts. Created with SMART Notebook 11.