This math packet is designed to help children watch and learn how to build teen numbers by looking for partners of 10 when a 9 is one of the partners. They must borrow a 1 from the other partner to create a 10. By creating a 10, it should enhance the mental math process. This packet provides the practice and support to make this happen more quickly and naturally. It can be completed whole class, in small groups or even individually. The packet also includes holiday themed cards so students can play reinforcement games to quicken and improve mental math skills.