9. Вычислите. 42 kg + 18 kg; 21 kg + 49 kg; 64 dm + 26 dm; 55 dm + 15 dm; 13 cm + 17 cm; 27 cm + 23 cm.

1. \(42\text{ kg}+18\text{ kg}=60\text{ kg}\).
2. \(21\text{ kg}+49\text{ kg}=70\text{ kg}\).
3. \(64\text{ dm}+26\text{ dm}=90\text{ dm}\).
4. \(55\text{ dm}+15\text{ dm}=70\text{ dm}\).
5. \(13\text{ cm}+17\text{ cm}=30\text{ cm}\).
6. \(27\text{ cm}+23\text{ cm}=50\text{ cm}\).

Ответ: 60 kg; 70 kg; 90 dm; 70 dm; 30 cm; 50 cm.