十一分之八减去七分之三减去十一分之三加上七分之四=(8/11-3/7)-(3/11+4/7)=8/11-3/7-3/11-4/7=(8/11-3/11)-(3/7+4/7)=5/11-1=-6/11
十一分之八减去七分之三减去十一分之三加上七分之四=8/11-3/11+(4/7-3/7)=5/11-1/7=35/77-11/77=24/77
8/11-3/7-3/11+4/7=(8/11-3/11)+(4/7-3/7)=5/11+1/7=46/77