1) 11,25 - 3 (5/12) + 4,3 - 7 (19/30) = 15,55 - 3 ( 25/60 ) - 7 ( 38/60 ) = 15,55 - 10 ( 63/60 ) = 15,55 - 11 ( 1/20 ) = 15,55 - 11,05 = 4,5
2) 7 (7/12) - 5 (5/6 ) = 7 (7/12 ) - 5 (10/12 ) = 6 (19/12) - 5 (10/12) = 1 (9/12 ) = 1 (3/4)
3) 4,5 : 1 (3/4) = (9/2) : ( 7/4) = 18/7 = 2 ( 4/7 )
Ответ 2 (4/7)