Вычислите: 1) 6,54 + 9/25; 2) 14 9/40 + 6,58; 3) 7/9 − 0,6; 4) 0,34 + 8/11.

1. \(6.54+\frac{9}{25}=6.54+0.36=6.9\).
2. \(14\frac{9}{40}+6.58=14.225+6.58=20.805\).
3. \(\frac{7}{9}-0.6=\frac{7}{9}-\frac{3}{5}=\frac{35-27}{45}=\frac{8}{45}\).
4. \(0.34+\frac{8}{11}=\frac{17}{50}+\frac{8}{11}=\frac{187+400}{550}=\frac{587}{550}=1\frac{37}{550}\).

Ответ: 1) 6,9; 2) 20,805; 3) \(\frac{8}{45}\); 4) \(1\frac{37}{550}\).