1. \(\frac{3}{8}+\frac{5}{14}\)

НОК(8, 14) = 56.

\[\frac{3}{8}+\frac{5}{14}=\frac{21}{56}+\frac{20}{56}=\frac{41}{56}.\]

Ответ: \(\frac{41}{56}\).