13/14 + 3/7 − 9/14 =

\[\frac{13}{14}+\frac{3}{7}-\frac{9}{14}=\frac{13}{14}+\frac{6}{14}-\frac{9}{14}=\frac{10}{14}=\frac{5}{7}\]

Ответ: \(\frac{5}{7}\)