\binom52 = \frac5 \cdot 42 = 10,\quad \binom72 = \frac7 \cdot 62 = 21,\quad \binom124 = \frac12 \cdot 11 \cdot 10 \cdot 94 \cdot 3 \cdot 2 \cdot 1 = 495 - Portal da Acústica