Fun! I'm going to do this for fluency next time I do math workshop in my class! You need as many Post-its as problems you will give, a Sharpie marker, and a pencil. Write the the first problem on the front of a Post-it note at the start (maybe this one is a different color). Now write the answer on another Post-it with a new problem on the underneath (in pencil). Students have to work problems and then search for the answers. Great way to get students doing math and get them up and moving!