№ 85. [4 1/3 : (5/6 + 0,25) / (7/12 - 2/15) : 0,9] - [3,6 * (7/12 + 1/9) / (5/8 - 1/3) * 1 5/7] = 3
1) 5/6 + 0,25 = 5/6 + 1/4 = 10/12 + 3/12 = 13/12
2) 4 1/3 : 13/12 = 13/3 * 12/13 = 12/3 = 4
3) 7/12 - 2/15 = 35/60 - 8/60 = 27/60 = 0,45
4) 0,45 : 0,9 = 0,5
5) 4 : 0,5 = 8
6) 7/12 + 1/9 = 21/36 + 4/36 = 25/36
7) 3,6 * 25/36 = 36/10 * 25/36 = 25/10 = 2,5
8) 5/8 - 1/3 = 15/24 - 8/24 = 7/24
9) 7/24 * 1 5/7 = 7/24 * 12/7 = 12/24 = 0,5
10) 2,5 : 0,5 = 5
11) 8 - 5 = 3