(1 5/6+2 4/9-1 3/4)*4-(3 1/2-1 7/10)*5 !

1)1 5/6 + 2 4/9 = 11/6 + 22/9 = (11 × 3 + 22 × 2)/18 = 33/18 + 44/18 =  77/18 = 4 5/18
2)4 5/18 - 1 3/4 = 7/18 - 7/4 =  (77 × 2 - 7 × 9)/36 = 154/36 - 63/36 =  91/36 = 2 19/36
3) 3 1/2  -  1 7/10 = 7/2  -  17/10 =  (7 × 5  -  17 × 1)/10 = 35/10  -  17/10 =  18/10 = 9/5 = 1 4/5
4) 2 19/36 * 4 = 91/36  *  4 =  91/9 = 10 1/9
5) 1 4/5 * 5 = 9/5  ×  5 =  9
6) 10 1/9 - 9 = 91/9  -  9/1=(91 × 1  -  9 × 9)/9 = 91/9  -  81/9 =  10/9 = 1 1/9
ответ : 1 1 /9