<p>Here’s a variation on the old SAT question I was finally able to locate.</p>
<p>A large solid cube is assembled by gluing together 125 identical unpainted small cubic blocks. All six faces of the large cube are then painted red. How many small cubic blocks have red paint on them?</p>
<p>From post #4:
</p>
<p>The large cube is 5x5x5, so the core is a 3x3x3 cube,
and there are 5^3 - 3^3 = 125-27 = 98 blocks with red paint on them.</p>