387. Найдите значение выражения: a) 1 + 28/9 + 2 + 5/12 + 7/9 + 4/12; в) 8 5/9 - (4 2/9 + 2 1/6); б) 5 3/5 - 3 15/25; г) (18 7/12 + 3 1/5) - 7 5/12

a) 1 + 28/9 + 2 + 5/12 + 7/9 + 4/12 = (1+2) + (28/9 + 7/9) + (5/12 + 4/12) = 3 + 35/9 + 9/12 = 3 + 35/9 + 3/4 = (108 + 140 + 27)/36 = 275/36

в) 8 5/9 - (4 2/9 + 2 1/6) = 8 5/9 - (4 4/18 + 2 3/18) = 8 5/9 - 6 7/18 = 8 10/18 - 6 7/18 = 2 3/18 = 2 1/6

б) 5 3/5 - 3 15/25 = 5 15/25 - 3 15/25 = 2

г) (18 7/12 + 3 1/5) - 7 5/12 = (18 7/12 - 7 5/12) + 3 1/5 = 11 2/12 + 3 1/5 = 11 1/6 + 3 1/5 = (11+3) + (1/6 + 1/5) = 14 + (5+6)/30 = 14 + 11/30 = 14 11/30