8+2-17
树上原来有5只小鸟,先飞来4只,又飞走了6只。树上还有几只小鸟?


2+6-4= 7-5+3= 9-6+7= 4+4-3= 3+6-7=
5-1+2= 2+8-7= 2+5-3= 1+6-4= 8-8+5=
9-6+2= 8-3-5= 1+7-2=
5+2-=4
6+5-4=5
8-43+4-5
7-7+104+5
3+3-26+2-5
10-7+15-0+5
8+2-510-6+2

8-7+3= 9-4+3= 7-2+4= 4+4-5=
10-2-8= 5+5-5= 8-3-2= 3+4-5=
3+1= 5+2= 4+3= 9-0= 4+3=
8-2= 4-2= 2+7= 7-7= 0+4=
0+0+2= 2+3-5= 2+2+2=
9-2+2= 8-0-4=
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