4.112.1) \(1,8\cdot(2\frac{1}{9}+1\frac{2}{3});\)

1) Вычислим \(2\frac{1}{9}+1\frac{2}{3}\):

$$2\frac{1}{9}+1\frac{2}{3} = 2\frac{1}{9}+1\frac{6}{9}=3\frac{7}{9} = \frac{3\cdot9+7}{9}=\frac{27+7}{9}=\frac{34}{9}$$

2) Вычислим \(1,8\cdot\frac{34}{9}\):

$$1,8\cdot\frac{34}{9} = \frac{18}{10} \cdot \frac{34}{9} = \frac{2}{10} \cdot 34 = \frac{34}{5} = 6,8$$

Ответ: 6,8