This lesson matches CC.4.OA.4, which says to gain familiarity with factors and multiples. In this lesson, the u-shaped method to find all the factors of a number is explained. While learning about factors of a number, prime and composite numbers are introduced. The lesson ends with a game created by using the activity builder in Smart Notebook 11. Two santas need their snowballs for their snowbeards. Each snowball has a number on it. Students must decide whether each number is prime or composite by finding its factors. This game can be played whole group or small groups. Enjoy!