(7-1 5/12):6,7+(5,75-3 1/6):15,5

(7 - 1 5/12) : 6,7 + (5,75 - 3 1/6) : 15,5 = 1,1) 7 - 1 5/12 = 6 12/12 - 1 5/12 = 5 7/12,2) 5 7/12 : 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 = 2 7/12,4) 2 7/12 : 15,5 = 31/12 : 155/10 = 31/12 * 10/155 = 1/6,5) 5/6 + 1/6 = 6/6 = 1