Question

Найдите сумму: 1/15 + 1/14х15+1/13х14+1/12х13+1/11х12

Answer 1

$\frac{14}{14*15} + \frac{1}{14*15} = \frac{15}{14*15} = \frac{1}{14}$
$\frac{1}{14} + \frac{1}{13*14} = \frac{1}{13}$
$\frac{1}{13} + \frac{1}{12*13}= \frac{1}{12}$
$\frac{1}{12} + \frac{1}{12*11} = \frac{1}{11}$