125 identical cubes are arranged in the form of a cubical block. How many cubes are surrounded by other cubes from each side?

1. **Identify the Structure ($n$):** The question gives 125 identical cubes. From my PYQ practice (specifically 2019 logic [22]), I instantly recognize that $125 = 5^3$. This means the block is a $5 \\times 5 \\times 5$ grid. So, $n=5$.\n\n2. **Translate the Condition:** The question asks for cubes 'surrounded by other cubes'. Comparing this to the 2017 Question 58 [7], this is exactly the same as asking for 'cubes with 0 painted faces' or the 'Inner Core'. These are the cubes trapped inside.\n\n3. **Apply the 'Peeling' Shortcut:** As per the 'Peeling the Onion' logic [53] [37], to get to the core, I just need to remove the outer layer from all sides. \n - The side length is 5.\n - Removing the outer layer reduces the side by 2 (one layer from left, one from right).\n - New side = $5 - 2 = 3$.\n\n4. **Final Calculation:** The answer is simply the volume of this inner core. \n - Inner Volume = $3^3 = 27$ [49].\n\nNo need to count or draw; the formula $(n-2)^3$ directly gives the answer.