This is a great way for your students to practice rounding numbers to the nearest 10 or 100. The cards will be hung around the room. The students can begin at any card. They start by solving the problem on their first card. Once they have the answer, they record it on the answer sheet. They will need to search the room for another card that has that answer on it. Once they find it they will then solve the new problem on that card. It is a great way to get the students up and moving. I like to incorporate it as one of my math workshop stations.