Задание 5. Найти значение выражения a) 7/12 + 9/12 - 5/12 б) 4 5/7 - 1 1/7 + 6 4/7 в) 8 - 4 5/6 г) 3/6 - 1/9

Пошаговое решение:

1. а) \( rac{7}{12} + rac{9}{12} - rac{5}{12} \)
   \( rac{7 + 9 - 5}{12} = rac{11}{12} \)
2. б) \( 4 rac{5}{7} - 1 rac{1}{7} + 6 rac{4}{7} \)
   \( (4 - 1 + 6) + (rac{5}{7} - rac{1}{7} + rac{4}{7}) = 9 + rac{5 - 1 + 4}{7} = 9 + rac{8}{7} = 9 + 1 rac{1}{7} = 10 rac{1}{7} \)
3. в) \( 8 - 4 rac{5}{6} \)
   \( 8 - (4 + rac{5}{6}) = 8 - 4 - rac{5}{6} = 4 - rac{5}{6} = 3 + 1 - rac{5}{6} = 3 + rac{6}{6} - rac{5}{6} = 3 rac{1}{6} \)
4. г) \( rac{3}{6} - rac{1}{9} \)
   Приведем дроби к общему знаменателю 18:
   \( rac{3  3}{6  3} - rac{1  2}{9  2} = rac{9}{18} - rac{2}{18} = rac{7}{18} \)