4 1/3(5/6+0.25)/(7/12-2/15)0.9-3.6(7/12+1/9)/(5/8-1/3)15/7

4 1/3 : (5/6 + 0,25) : (7/12 - 2/15) : 0,9 - 3,6 * (7/12 + 1/9) : (5/8 - 1/3) * 15/7 = -8 1948/3969.

1) 5/6 + 0,25 = 5/6 + 1/4 = 10/12 + 3/12 = 13/12 = 1 1/12;

2) 7/12 - 2/15 = 35/60 - 8/60 = 27/60 = 9/20;

3) 7/12 + 1/9 = 21/36 + 4/36 = 25/36;

4) 5/8 - 1/3 = 15/24 - 8/24 = 7/24;

5) 4 1/3 : 1 1/12 = 13/3 : 13/12 = 13/3 * 12/13 = 12/3 = 4;

6) 4 : 9/20 = 4 * 20/9 = 80/9 = 7 8/9;

7) 80/9 : 0,9 = 80/9 * 10/9 = 800/81 = 9 71/81;

8) 3,6 * 25/36 = 36/10 * 25/36 = 25/10 = 2,5;

9) 25/10 : 7/24 = 25/10 * 24/7 = 5/2 * 24/7 = (5 * 2 * 12)/(2 * 7) = 60/7 = 8 4/7;

10) 60/7 * 15/7 = 900/49 = 18 18/49;

11) 9 71/81 - 18 18/49 = 9 - 18 + 71/81 - 18/49 = -9 + 3479/3969 - 1458/3969 = -9 + 2021/3969 = -8 1948/3969.