1. $$P_5 + \frac{A_3^3}{C_5^5} = 5! + \frac{3!}{\frac{5!}{5!(5-5)!}} = 120 + \frac{6}{\frac{5!}{5! \cdot 0!}} = 120 + \frac{6}{1} = 120 + 6 = 126$$
Ответ: 126