Пошаговое объяснение:

а) 5. 7/12 + 1. 1/3 = 5. 7/12 + 1. 4/12 = 6. 11/12

б) 6. 3/50 - 3. 17/75 = 6. 9/150 - 3. 34/150 = 5. 159/150 - 3. 34/150 = 2. 125/150 = 2. 5/6

в) 5. 6/55 + 3. 9/44 - 4. 7/22 = 5. 24/220 + 3. 45/220 - 4. 70/220 = 8. 69/220 - 4. 70/220 = 7. 289/220 - 4. 70/220 = 3. 219/220