560-557+554-551+……+500-49 - 知识问答

560-557+554-551+……+500-497

2个回答

(560-557)+(554-551)+……+(500-497)
规律：每两个一组,被减数和减数每次减少6,差不变都=3
一共有60/6+1=11组.
560-557+554-551+……+500-497
=3*11
=33

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