Count All Layers
Stacks may be 1, 2, or 3 layers tall. Count each layer separately, then add them up.
Tip: Start at the bottom and work upward.
Don't Forget Hidden Supports
A cube high in the stack must be supported by cubes below it, even if you can't see them.
Tip: If you can see a cube on top, mentally add all the cubes directly underneath.
Read the Iso View Carefully
Iso view shows the TOP face of each cube as a rhombus, the LEFT face as a tilted parallelogram, the RIGHT face as another parallelogram.
Tip: Top faces with hatching make it easier to spot how many cubes are 'on the roof'.
Subtract Empty Spaces
When the stack has a notch or step, count the FULL block (e.g., 2x2x2 = 8) and subtract the missing cubes.
Tip: Sometimes it's quicker to count what's missing than what's there.