495+328=?,293+496=?,909+777=?
774-94=?,950-656=?,1570-770=?
23+?=823,285+?=1133,1269+?=1611
36*7=?,9*482=?,849*5=?
144/3=?,720/8=?,1770/6=?
---
?-217=869-452,179+162+473+374=?
743-263=?+355,528+462+493-1213=?
209+?+303=973,1013+595-418-937=?
221+?-531=579,2173-640-752-495=?
495+328=
293+496=
909+777=
774-94=
950-656=
1570-770=
23+=823
285+=1133
1269+=1611
36×7=
9×482=
849×5=
144÷3=
720÷8=
1770÷6=
-217=869-452
179+162+473+374=
743-263=+355
528+462+493-1213=
209++303=973
1013+595-418-937=
221+-531=579
2173-640-752-495=
雾霾空气污染
