2) 7/15 : (6/10 − 8/3) + 19 · 2/31

\(\frac{6}{10}-\frac{8}{3}=\frac{3}{5}-\frac{8}{3}=-\frac{31}{15}\).

\(\frac{7}{15}:\left(-\frac{31}{15}\right)=-\frac{7}{31}\), а \(19\cdot\frac{2}{31}=\frac{38}{31}\).

\(-\frac{7}{31}+\frac{38}{31}=1\).

Ответ: 1.