(2 1.4 -5.6):(3-1.6)+29.75:6.8-1.2:0.64=

Решим пример по действиям:

1) 21,4 - 5,6 = 15,8;

2) 3 - 1,6 = 1,4;

3) 15,8 : 1,4 = 158/10 * 10/14 = (158 * 10)/(10 * 14) = 158/14 = 79/7;

4) 29,75 : 6,8 = 2975/100 * 10/68 = (2975 * 10)/(100 * 68) = 175/(10 * 4) = 35/8;

5) 1,2 : 0,64 = 12/10 * 100/64 = (12 * 100)/(10 * 64) = 15/8;

6) 79/7 + 35/8 - 15/8 = 79/7 + (35 - 15)/8 = 79/7 + 20/8 = 79/7 + 5/2 = 158/14 + 35/14 = (158 + 35)/14 = 193/14.

Ответ: 193/14.