In the pictures below, you will see how the students found the volumes of their pencil boxes.
Through this experience, they learned a short-cut method, which is to multiply the length (l) by the width (w) and then multiply that by the height (h).
l x w x h = volume (in cubic units)
More information about volume can be found below:
Kahn Academy: Volume: Measuring with Unit Cubes (Video)
Introducing Volume (You Tube Video)
Kids Math: Finding the Volume of a Cube or Box
Game: Volume Shapes Shoot