Ответ:
\(0,8:0,9=\frac{8}{9}\), \(0,4=\frac{2}{5}\).
\(\frac{8}{9}+\frac{2}{5}=\frac{40}{45}+\frac{18}{45}=\frac{58}{45}=1\frac{13}{45}\).
Ответ: \(1\frac{13}{45}\).
\(0,8:0,9=\frac{8}{9}\), \(0,4=\frac{2}{5}\).
\(\frac{8}{9}+\frac{2}{5}=\frac{40}{45}+\frac{18}{45}=\frac{58}{45}=1\frac{13}{45}\).
Ответ: \(1\frac{13}{45}\).