Problem 23 · 2025 Math Kangaroo
Stretch
Spatial & Visual Reasoning
cube-viewscomposition
Tina wants to combine the three building blocks shown in the picture to form a cube building. Which one of the following cube buildings could she make? (The three blocks and the five choices A–E are pictured with the question.)
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Answer: D
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Hint 1 of 2
First just count: how many little cubes are in the three blocks all together? The answer building must use exactly that many cubes.
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Hint 2 of 2
Throw out any choice with the wrong cube count, then check the survivors by mentally snapping the three blocks together.
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Approach: count cubes first, then fit the blocks
- Each of the three building blocks is made of small cubes; counting them gives a fixed total number of cubes that the finished building must contain.
- Count the cubes in each answer building and cross out the ones with the wrong total — the right building must have exactly as many cubes as the three blocks combined.
- Among the buildings with the correct cube count, only (D) can actually be assembled from those three particular blocks fitting together with no gaps, so the answer is (D).
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