A powerful strategy for this section is to count all the cubes with painted surfaces by making a tally chart on the test sheet.
Start counting from the top-front (the cube closest to you on the highest level) and work your way back on the same level. Once you are done with that level, go down a level below and repeat the process. This strategy will ensure you don’t miss any cubes, and you’ll also have answers for the next 2-3 questions, since a cube structure is used in more than one question.
Make sure you pay close attention to the hidden cubes as well!