Building bugs is a fun way to practice adding and subtracting multi digit numbers. Students take turns answering questions. If they answer it correct they get to roll a die and see which bug part they get to add. Laminate your bugs so that you can use them over and over to review this and other concepts. There is a form A and B for 3 different levels. Easy: 2 digit no regrouping, Medium: 2 digit with regrouping and 3 digit no regrouping, Hard: 2 and 3 digit with regrouping.