الف) $4! = (4 \times 3 \times 2 \times 1) = 24$ ب) $\frac{5!}{3!} = \frac{5 \times 4 \times (3 \times 2 \times 1)}{(3 \times 2 \times 1)} = 5 \times 4 = 20$ پ) $\frac{10!}{7!} = \frac{10 \times 9 \times 8 \times 7!}{7!} = 720$ ت) $\frac{3! \times 5!}{7!} = \frac{3! \times 5!}{7 \times 6 \times 5!} = \frac{6}{7 \times 6} = \frac{1}{7}$