Question

Calculați:
5! Supra 3! + 6! Supra 4! + 7! Supra 5! = ?

Answer 1

$\frac{5!}{3!}+ \frac{6!}{4!} + \frac{7!}{5!}$
$\frac{3!*4*5}{3!} + \frac{4!*5*6}{4!} + \frac{5!*6*5}{5!}$
4*5 + 5*6 + 5*6 = 80