1.2. Вычислите значение числового выражения: 1) \(14\frac{7}{15}-3\frac{3}{23}\cdot\frac{23}{27}-1\frac{1}{5}\cdot\frac{1}{6}\); 2) \(\left(5\frac{8}{9}:1\frac{17}{36}+1\frac{1}{4}\right)\cdot\frac{5}{21}\); 3) \((-3,25-2,75):(-0,6)+0,8\cdot(-7)\); 4) \(\left(-1\frac{3}{8}-2\frac{5}{12}\right):5\frac{5}{12}\).

1) \(14\frac{7}{15}=\frac{217}{15}\), \(3\frac{3}{23}=\frac{72}{23}\), поэтому \(3\frac{3}{23}\cdot\frac{23}{27}=\frac{72}{27}=\frac{8}{3}\). Также \(1\frac{1}{5}\cdot\frac{1}{6}=\frac{6}{5}\cdot\frac{1}{6}=\frac{1}{5}\).

\(\frac{217}{15}-\frac{8}{3}-\frac{1}{5}=\frac{217-40-3}{15}=\frac{174}{15}=\frac{58}{5}=11\frac{3}{5}\).

2) \(5\frac{8}{9}=\frac{53}{9}\), \(1\frac{17}{36}=\frac{53}{36}\), поэтому \(\frac{53}{9}:\frac{53}{36}=4\).

\((4+1\frac{1}{4})\cdot\frac{5}{21}=\frac{21}{4}\cdot\frac{5}{21}=\frac{5}{4}=1\frac{1}{4}\).

3) \((-3,25-2,75):(-0,6)+0,8\cdot(-7)=(-6):(-0,6)-5,6=10-5,6=4,4\).

4) \(-1\frac{3}{8}=-\frac{11}{8}\), \(2\frac{5}{12}=\frac{29}{12}\), \(5\frac{5}{12}=\frac{65}{12}\).

\(\left(-\frac{11}{8}-\frac{29}{12}\right):\frac{65}{12}=\left(-\frac{33}{24}-\frac{58}{24}\right)\cdot\frac{12}{65}=-\frac{91}{24}\cdot\frac{12}{65}=-\frac{7}{10}\).

Ответ: 1) \(11\frac{3}{5}\); 2) \(1\frac{1}{4}\); 3) \(4,4\); 4) \(-\frac{7}{10}\).