To find the answer you need to add the volumes of all of the cubes. The volume of a cube = L^3 where L is the length of an edge. Since each cube has edges of L = 1/2 inch, L^3 = (1/2)^3 inch^3 = 1/8 inch^3.
Since there are 1120 cubes in the prism, the total volume of the prism is:
V = 1120 * 1/8 inch^3 = 140 inch^3.
