8. Вычислите значение выражения по действиям: 1) 10 · (3 2/15 − 2 5/18) + 12 (1 5/6 + 5 3/4); 2) (2 1/4 + 3 2/3) : (8,5 − 1 2/5) · 1,2.

1. \(10\left(3\frac{2}{15}-2\frac{5}{18}\right)+12\left(1\frac{5}{6}+5\frac{3}{4}\right)\)

   \(=10\left(\frac{47}{15}-\frac{41}{18}\right)+12\left(\frac{11}{6}+\frac{23}{4}\right)\)

   \(=10\cdot\frac{77}{90}+12\cdot\frac{91}{12}=\frac{77}{9}+91=\frac{896}{9}=99\frac{5}{9}\).

2. \(\left(2\frac{1}{4}+3\frac{2}{3}\right):(8.5-1\frac{2}{5})\cdot1.2\)

   \(=\frac{71}{12}:\frac{71}{10}\cdot\frac{6}{5}=\frac{71}{12}\cdot\frac{10}{71}\cdot\frac{6}{5}=1\).

Ответ: 1) 99 5/9; 2) 1.