The answer is 13 triangles.
The shape is one big triangle subdivided into 9 smallest unit triangles — a lattice with side 3. Count every triangle by size and direction, and don’t stop at the obvious ones.
Upright triangles:
- Size 1 (the smallest): 6
- Size 2 (made of 4 small ones): 3
- Size 3 (the whole figure): 1
That’s 6 + 3 + 1 = 10 upright.
Inverted triangles:
- Size 1 (small upside-down ones in the middle): 3
- Larger inverted: 0 — the lattice doesn’t contain any.
10 + 3 = 13.
Here’s where the guesses split. If you only counted the upright triangles, you stopped at 10 — and 10 is the most common wrong answer. If you found the 3 little upside-down triangles hiding in the center but missed a size-2, you landed on 12 or 11. The full count needs both directions AND all three sizes: 6 + 3 + 1 upright, plus 3 inverted, equals 13 exactly.
Did you land on 13, or did the upside-down three get past you? Be honest in the comments — and watch our page for tomorrow’s counting game.
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