(2.75:3 целых 2/3-2 целых 1/3:1.75)*три целых 2/21 = - 1 29/36
1) 2,75 : 3 2/3 = 2 3/4 : 3 2/3 = 11/4 : 11/3 = 3/4
2) 2 1/3 : 1,75 = 2 1/3 : 1 3/4 = 7/3 : 7/4 = 4/3 = 1 1/3
3) 3/4 - 1 1/3 = 9/12 - 16/12 = - 7/12
4) - 7/12 * 3 2/21 = - 7/12 * 65/21 = - 65/36 = - 1 29/36