This product does require some prep but afterwards you will have a ready made center to use with your students year after year. Learning Concept - addition - sums 1-12, Looking at patterns in addition, build addition fluency Materials: 4 sets of monster cards labeled with numerals 1-12 in 4 different colors so that 4 students or 4 partners can work on the activity at the same time. 1 set of all addition sentences that will make sums 1=12 1 blank page for filling out addition sentences for each numeral 1-12 1 answer sheet for addition sentences page Prep Print, laminate and cut out the monster cards. Print 4 copies of the math sentences cards, laminate and cut apart Store each set of colored monsters and addition cards in a Ziploc bag or container so that you have 4 sets ready to go. Use Students sort addition sentences under the monster card that is the sum of the sentence. For example, 3+2 would go under the numeral 5 monster. Once all sorted, they can fill out the addition chart Future use - tape or glue addition charts into math notebooks so that students can refer to it when adding. Use the charts to discuss the patterns seen in addition such as ascending and descending numerals and inverse principle of addition. This is a great activity for remediation for students that need addition practice and fluency. It can be an independent or small group activity in 2nd, 3rd and 4th grade and for resource room teachers. I hope that you and your students enjoy this addition center.