I always make two versions of a test and pass them out checkerboard style. I ask students to show work on tests or quizzes.
My students did a lot of these problems graphically during the unit and I will accept this as an acceptable method for finding the solutions to problems on this test. That means that some of these problems may be light on work. I do warn the students that this may be a detriment to them as I give partial credit when work is present. I also tell them that the best choice is to solve or simplify each problem algebraically and check their work graphically.
I offer a variety of Extra Credit puzzle for students who finish early and have no make up work to complete. This includes, but is not limited to; sudoku, mathdoku, logic problems, picture mazes, and pixel puzzles. A couple of my favorites are: Griddlers and Conceptis puzzles
Both sites offer a number of free puzzles as well as purchasable books. Pixel Puzzles are a particular favorite. The Mathdoku are also great. They can increase a student's numeracy abilities if done regularly.