Ответ:

Пошаговое объяснение:

1) 7 4/21 + 2 1/6 = 151/21 + 13/6 = 302/42 + 91/42= 393/42 =131/14 = 9 5/14

2) 3 5/36 - 1 19/45 = 3 25/180 - 1 76/180 = 2 205/180 - 1 76/180 = 1 129/180 = 1 43/60

3)

3 7/30 - ( 4 1/6 - 1 2/15) + (4 5/9 - 4 5/9)= 1/5

1) 4 1/6 - 1 2/15 = 4 5/30 - 1 4/30 = 3 1/30

2) 3 7/30 - 3 1/30 = 6/30 = 1/5

3) 4 5/9 - 4 5/9 = 0

4) 1/5 + 0 = 1/5

4)

(2 7/12 + 6 8/9) - ( 5- 1 7/36 - 3 1/3) = 9

1) 2 7/12 + 6 8/9 = 2 21/36+ 6 32/36 = 8 53/36 =9 17/36

2) 5 - 1 7/36 = 4 36/36 - 1 7/36 = 3 29/36

3) 3 29/36- 3 1/3 = 3 29/36 - 3 12/36 = 17/36

4) 9 17/36 - 17/36 = 9