числитель:
1) 0,9 - 1/3 + 0,75 - 1/15 = (0,9 + 0,75) - (1/3 + 1/15) = 1,65 - (5/15 + 1/15) =
= 1,65 - 6/15 = 1,65 - 0,4 = 1,25,
2) 0,5 - 1/6 = 5/10 - 1/6 = 15/30 - 5/30 = 10/30 = 1/3,
3) 1,25 : 1/3 = 125/100 * 3 = 375/100 = 3,75,
4) 3,75 : 5/12 = 375/100 * 12/5 = 9,
знаменатель:
5) 5/7 - 0,4 + 11/14 = 5/7 - 4/10 + 11/14 = 50/70 - 28/70 + 55/70 = 77/70 =
= 11/10 = 1 1/10 (или 1,1),
6) 2/3 + 0,8 - 7/15 = 2/3 + 8/10 - 7/15 = 20/30 + 24/30 - 14/30 = 30/30 = 1,
7) 1,1 : 1 = 1,1,
8) 1,1 : 2 1/5 = 11/10 : 11/5 = 11/10 * 5/11 = 5/10 = 1/2 (или 0,5),
9) 9 : 0,5 = 18,
ответ: 18