At the heart of this problem is a model of a six story building made with cubes. There are a few questions designed to get students to see different ways to think about the structure of the model. First they are asked to calculate the total number of cubes in the model. Then they are asked to calculate the total number of cubes if the height of the model is doubled (Hint: The number of cubes is not doubled!). Then they are asked how they would figure out the number of cubes in the model for any height.

I highly recommend having blocks like those below available for your students. It will help them explore and talk about their different ways of seeing.