А) 3+8 5/12=(3+8)+5/12= 11 5/12
б) 10 6/7-3 = (10-3)+6/7=7 6/7
в) 4 2/13 + 5 7/13= (4+5)+(7/13+2/13)=9 9/13
г) 8 7/12 - 4 2/12 =(8-4)+(7/12-2/12)= 4 5/12
д) 4 8/11 + 5 7/11 =(4+5)+(8/11+7/11) =9 15/11 = 10 4/11
е) 7 5/9 - 2 8/9 = 6 14/9-2 8 /9 = (7-2)+(5/9-8/9)=4 6/9 = 4 2/3
ж) 7-3/8= 6 8/8-3/8 = 6 5/8
з) 10 - 3 7/15= 9 15/15-3 7/15 = (10-3)+7/15 =6 8/15