(2 1/255-(2 11/121/2+7 11/12)):5/16+(28-31 1/2=

Распишем пример по порядку исполненья деяний:

1) 2 11/12 1/2 = 35/12 1/2 = 35/24 = 1 11/24;

2) 1 11/24 + 7 11/12 = 35/24 + 95/12 = (35 * 1 + 95 * 2)/24 = (35 + 190)/24 = 225/24 = 75/8 = 9 3/8;

3) 2 1/25 5 = 51/25  5 = 51/5 = 10 1/5;

4) 10 1/5 - 9 3/8 = 51/5 - 75/8 = (51 * 8 - 75 * 5)/40 = (408 - 375)/40 = 33/40;

5) 28 - 31 1/2 = 28/1 - 63/2 = (28 * 2 - 63 * 1)/2 = (56 - 63)/2 = -7/2 = -3 1/2;

6) 33/40 : 5/16 = 33/40 * 16/5 = 33/5 * 2/5 = 66/25 = 2 16/25;

7) 2 16/25 + (-3 1/2) = 2 16/25 - 3 1/2 = 66/25 - 7/2 = (66 * 2 - 7 * 25)/50 = (132 - 175)/50 = -43/50.

Ответ: -43/50.