This interactive SMARTBOARD lesson is a fun way for students to practice their addition and subtraction facts up to 20. Move the bow ties to the big red tie in the middle with the answer. If they are correct, the bow tie disappears. If it is not correct, the bow tie will bounce back. All slides are self correcting with this feature. Great way to review or practice facts. Use in a center, small group, or partner work. Even a great way to spend 20 minutes before lunch, recess, or starting the morning off with some fun practice. SMART Notebook is necessary to download this lesson. Created for grades 1-4 depending on the level and use of the students.