а) 1 7/9 + 28 + 2 5/12 + 5 2/9 + 7/12 + 4 3/4 = 1 + 7/9 + 28 + 2 + 5/12 + 5 + 2/9 + 7/12 + 4 + 3/4 == 1 + 28 + 2 + 5 + 4 + 7 + 3 + 7 + 2 + (7/9 + 5/12 + 2/9 + 7/12 + 3/4) == 50 + 1 + 5 + 3 + (28/36 + 15/36 + 8/36 + 21/36 + 27/36) == 59 + 1 + 5 + 3 + 99/36 = 68 3/4
б) 5 3/5 - 3,15 + 7 12/25 = 5 + 3/5 - 3,15 + 7 + 12/25 == 5 - 3,15 + 7 + 3/5 + 12/25 = 5 + 7 + 3/5 + 12/25 - 3,15 == 12 + 3/5 + 12/25 - 3,15 = 12 + 3/5 + 12/25 - 3 - 3/20 == 12 + 3/5 + 12/25 - 310/100 = 12 + 18/25 - 310/100 == 12 + 18/25 - 124/25 = 12 + (18 - 124)/25 = 12 - 106/25 = 12 - 4 6/25 = 7 19/25
в) 8 5/9 - (4 2/9 + 2 1/6) = 8 + 5/9 - 4 - 2/9 - 2 - 1/6 == 8 - 4 - 2 - 5/9 - 2/9 - 1/6 = 4 - 7/9 - 1/6 = 4 - 56/36 - 6/36 == 4 - 62/36 = 4 - 1 26/36 = 2 10/36 = 2 5/18
г) (18 7/12 + 3 1/5) - 7 5/12 = 18 + 7/12 + 3 + 1/5 - 7 - 5/12 == 18 + 3 + 7/12 + 1/5 - 7 - 5/12 = 21 + 7/12 + 1/5 - 7 - 5/12 == 21 - 7 + 7/12 + 1/5 - 5/12 = 14 + 7/12 + 1/5 - 5/12 == 14 + 5/60 + 12/60 - 5/60 = 14 + 17/60 = 14 17/60
а) 1 7/9 + 28 + 2 5/12 + 5 2/9 + 7/12 + 4 3/4 = 1 + 7/9 + 28 + 2 + 5/12 + 5 + 2/9 + 7/12 + 4 + 3/4 =
= 1 + 28 + 2 + 5 + 4 + 7 + 3 + 7 + 2 + (7/9 + 5/12 + 2/9 + 7/12 + 3/4) =
= 50 + 1 + 5 + 3 + (28/36 + 15/36 + 8/36 + 21/36 + 27/36) =
= 59 + 1 + 5 + 3 + 99/36 = 68 3/4
б) 5 3/5 - 3,15 + 7 12/25 = 5 + 3/5 - 3,15 + 7 + 12/25 =
= 5 - 3,15 + 7 + 3/5 + 12/25 = 5 + 7 + 3/5 + 12/25 - 3,15 =
= 12 + 3/5 + 12/25 - 3,15 = 12 + 3/5 + 12/25 - 3 - 3/20 =
= 12 + 3/5 + 12/25 - 310/100 = 12 + 18/25 - 310/100 =
= 12 + 18/25 - 124/25 = 12 + (18 - 124)/25 = 12 - 106/25 = 12 - 4 6/25 = 7 19/25
в) 8 5/9 - (4 2/9 + 2 1/6) = 8 + 5/9 - 4 - 2/9 - 2 - 1/6 =
= 8 - 4 - 2 - 5/9 - 2/9 - 1/6 = 4 - 7/9 - 1/6 = 4 - 56/36 - 6/36 =
= 4 - 62/36 = 4 - 1 26/36 = 2 10/36 = 2 5/18
г) (18 7/12 + 3 1/5) - 7 5/12 = 18 + 7/12 + 3 + 1/5 - 7 - 5/12 =
= 18 + 3 + 7/12 + 1/5 - 7 - 5/12 = 21 + 7/12 + 1/5 - 7 - 5/12 =
= 21 - 7 + 7/12 + 1/5 - 5/12 = 14 + 7/12 + 1/5 - 5/12 =
= 14 + 5/60 + 12/60 - 5/60 = 14 + 17/60 = 14 17/60