Geometry 3D

This problem is so cunfusing

For this problem, the solution seems to break down the 16 number of cubes to find how many possible can be formed, but why are we forgetting to calculate the side with it? I assumed we multiply the 16 with the Surface area of each which is 216 and then distribute the possible factors

What do you mean? We only need to find out the number of such solids.

does the side length even matter in this ?

What do you think?