香蕉:15.6-3.3=12.3西瓜:15.6两个加起12.3+15.6=27.9
15.6-3.3+15.6=27.9
15.6×2-3.3=27.9
15.6-3.3+15.6=
28.9元
15.6－3.3+15.6＝27.9
