2-1+3-2+4-3+……+50-49+51-50

来源：学生作业学帮网编辑：学帮网时间：2024/05/24 04:23:41

2-1+3-2+4-3+……+50-49+51-50
=(2-1)+(3-2)+.+(50-49)+(51-50)
=1+1+.+1
=1*50
=50

两个两个一组有50个-1