12+23-34+45-56+67-78+89加减巧算怎么算

2024-12-05 04:20:52
推荐回答(4个)
回答1:

12+23-34+45-56+67-78+89
把顺序换下: (89-78)+(67-56)+(45-34)+23+12=33+23+12=68

回答2:

12+23-34+45-56+67-78+89
=12+45+89-78+(23+67)-(34+56)
=67+11
=78

回答3:

12+23-34+45-56+67-78+89
=12+(23+67)-(34+56)+45-78+89
=12+45-78+89
=57+11
=68

回答4:

45-34+67-56+89-78+12+23
=11+11+11+12+23
=68