30,25 : 4 5/7 : 1,05 - 2 1/6 = 3 целых 17/18
1) 30,25 : 4 5/7 = 3025/100 : 33/7 = 121/4 * 7/33 = (11*7)/(4*3) = 77/12
2) 77/12 : 1,05 = 77/12 : 105/100 = 77/12 * 100/105 = (11*25)/(3*15) = 275/45 = 55/9 = 6 1/9
3) 6 1/9 - 2 1/6 = 6 2/18 - 2 3/18 = 5 20/18 - 2 3/18 = 3 17/18