8.1/3*9-4.1/3*3.1/4-2.2/7*3.5/24=

8 1/3 * 9 - 4 1/3 * 3 1/4 - 2 2/7 * 3 5/24 = 53 7/12.

1) 8 1/3 * 9 = (8 * 3 + 1) / 3 * 9 = (24 + 1) / 3 * 9 = 25/3 * 9 = (25 * 9) / 3 = (25 * 3 * 3) / 3 = 25 * 3 = 75;

2) 4 1/3 * 3 1/4 = (4 * 3 + 1) / 3 * (3 * 4 + 1) / 4 = (12 + 1) / 3 * (12 + 1) / 4 = 13/3 * 13/4 = (13 * 13) / (3 * 4) = 169/12 = 14 (169 - 14 * 12) / 12 = 14 (169 - 168) / 12 = 14 1/12;

3) 2 2/7 * 3 5/24 = (2 * 7 + 2) / 7 * (3 * 24 + 5) / 24 = (14 + 2) / 7 * (72 + 5) / 24 = 16/7 * 77/24 = (8 * 2 * 7 * 11) / (7 * 8 * 3) = 22/3 = 7 1/3;

4) 75 - 14 1/12 = 60 11/12;

5) 60 11/12 - 7 1/3 = 60 - 7 + 11/12 - 4/12 = 53 7/12.