A great, hands-on way to build basic fact mastery and promote number sense. Students can have their own sheet to cut and sort on their own, or teachers can cut and laminate the cards and have the students sort in a small group in a math center. The students could also cut and glue into their math journal or on to a piece of construction paper. They could also keep the cards and headings in a ziploc bag to work on when they have free time, or take home to do for homework to promote family involvement. So many choices! Check out my Ways to Make 18 color sheet in which the students color the boxes if they make to and X them out if they are not equal to 18. A great follow-up to this center! Also check out my worksheets and centers for Ways to Make 10, 12 (FREEBIE!), 15, 20 and 25! Let me know if there any others I can create for you or if I can edit the activity to fit your needs. Thanks!