65. Найдите значение выражения: 1) 8 1/3 · 9 − 2 2/3 · 3 1/4 · 3 5/24; 2) 1 1/48 · 2 2/5 − (9 1/6 · 1/15 + 2 5/9) · 1/4.

\(8\frac13\cdot9-2\frac23\cdot3\frac14\cdot3\frac5{24}=75-\frac83\cdot\frac{13}{4}\cdot\frac{77}{24}=75-\frac{1001}{36}=\frac{1699}{36}=47\frac{7}{36}.\)

\(1\frac1{48}\cdot2\frac25=\frac{49}{48}\cdot\frac{12}{5}=\frac{49}{20}.\)

В скобках: \(9\frac16\cdot\frac1{15}+2\frac59=\frac{55}{6}\cdot\frac1{15}+\frac{23}{9}=\frac{11}{18}+\frac{46}{18}=\frac{19}{6}.\)

Тогда \(\frac{49}{20}-\frac{19}{6}\cdot\frac14=\frac{49}{20}-\frac{19}{24}=\frac{199}{120}=1\frac{79}{120}.\)