(7- 1 целая 5/12):6,7+(5,5-3 целых 1/6) : 15,5

(7 - 1 5/12) : 6,7 + (5,75 - 3 1/6) : 15,5 = (84/12 - 17/12) : 67/10 + (1725/300 - 950/300) : 155/100 = 67/12 * 10/67 + 31/12 * 100/155 = 5/6 + 1/6 =6/6 = 1
по действиям:
1) 7-1 5/12 = 7-17/12=84/12-17/12=67/12,
2) 67/12:6,7=67/12:67/10=67/12*10/67=10/12= 5/6,
3) 5,75-3 1/6 = 575/100-19/6 = 1725/300-950/300=775/300=31/12= 2 7/12,
4) 31/12:15,5=31/12:155/10=31/12*10/155 = 1/6,
5) 5/6 + 1/6 = 6/6 = 1