Will and Mike are using the "leveling" strategy to find the mean of three numbers, 1, 2 and 4. They started with 7 cubes and are rearranging them among the three towers, with two cubes in each tower. Mike thinks they are done, that the mean of the three numbers is 2. Will thinks they need to do something with the extra cube. Who is correct? Explain your answer. What is the mean for these three numbers and how it could be seen in the towers