This video is a math lesson on how to add within 20 by using a ten frame. The video starts by explaining the concept of adding and the different ways to make 10. It also reviews the commutative property of addition. The video then introduces the ten frame as a tool to help visualize numbers and group them when adding. The lesson demonstrates how to use the ten frame to add 9 and 6, and also adds 4 and 7, and 12 and 6.