Question 986429
The cake has two 6x6 faces  (top and bottom)
It also has 4 6x4 faces (the 4 sides)

On the 6x6 face you have a 4x4 unit square that is not touching an edge. So there are 16 on each of those faces. Thats 32 units.

On each 4x6 face, there is a 2x4 square that is not touching any edge. So that is 8 units. Times four faces gives another 32 units

Total 64 units have a single frosted face.