1-2+3-4+5-6+⋯98+99等于?
来源:学生作业帮助网 编辑:作业帮 时间:2024/06/22 03:39:06
![1-2+3-4+5-6+⋯98+99等于?](/uploads/image/z/183937-49-7.jpg?t=1-2%2B3-4%2B5-6%2B%26%238943%3B98%EF%BC%8B99%E7%AD%89%E4%BA%8E%3F)
1-2+3-4+5-6+⋯98+99等于?
1-2+3-4+5-6+⋯98+99等于?
1-2+3-4+5-6+⋯98+99等于?
原式=(1-2)+(3-4)+(5-6)+…+(97-98)+99
=(-1)+(-1)+(-1)+…+(-1)+99 【有49个(-1)】
=-49+99
=50
-49+99=50
!!!!!!!!!!!
原式=(1-2)+(3-4)+…+(97-98)+99
=-1×98÷2+99
=-49+99
=50
1-2+3-4+5-6+....-98+99
=1+(-2+3)+(-4+5)+(-6+7+,,,+(-98+99)
=1+1*49
=50
解1-2+3-4+5-6+⋯98+99
=(1-2)+(3-4)+(5-6)+⋯+(97-98)+99
=49×(-1)+99
=-49+99
=50