This math topic focuses on calculating the surface area of rectangular prisms by counting the number of blocks that have zero outside faces exposed. The problems presented involve various dimensions of rectangular prisms, requiring learners to visualize the three-dimensional shapes and determine how many blocks within these prisms are completely enclosed by other blocks, thus having no external faces. The questions are structured to build understanding of the concept of surface area in the context of geometry, specifically pertaining to three-dimensional shapes. Each problem provides multiple-choice answers, enhancing problem-solving skills centered around spatial reasoning and geometry.

Work on practice problems directly here, or download the printable pdf worksheet to practice offline.